I've started this thread in an effort to create a comprehensive list of everyone Batman has ever killed in the comics, whether by accident or intent. I've tried to provide scans for as many examples as possible.
Hopefully people will add to list with other examples that I've overlooked. But for now, here are some that I've found.
The Case of the Chemical Syndicate - Detective Comics #27 (1939): he punches Stryker into a vat of acid
Justice: Detective Comics #28 (1939) - he throws one of Frenchy Blake's henchmen off a roof
The Batman Meets Doctor Death - Detective Comics #29 (1939): he kills Jabah by lassoing a rope around his neck and breaking it
Return of Doctor Death - Detective Comics #30 (1939): he kills Mikhail by breaking his neck with a well-aimed kick
Batman Versus the Vampire (Part II) - Detective Comics #32 (1939): he shoots Dala and the Monk dead while they are asleep
The Batman Wars Against the Dirigible of Doom - Detective Comics #33 (1939): he carries a gun and uses it to shoot some machinery aboard a dirigible, causing an explosion that kills a number of henchmen. He later switches clothes with another bad guy and places him in a death chamber to die in his place. At the end of the story he kills Dr. Krueger by knocking him out with gas pellets and causing his plane to crash
Peril in Paris - Detective Comics #34 (1939):he knocks out the Duc D'Orterre and leaves him to drive over a cliff
The Case of the Ruby Idol - Detective Comics #35 (1940): he kicks an opponent onto another villain's sword, impaling him. Later he knocks Lenox out of a window to his death
The Screaming House - Detective Comics #37 (1940): he knocks Count Grutt against a sword that impales him through the head
The Giants of Hugo Strange - Batman #1 (1940): he open fires on a group of gangsters using the Batplane's machine gun. One of the bad guys escapes, so Batman drops a cable from the Batplane and hangs him. At the end of the story he uses gas pellets to knock the last bad guy off a rooftop
The Horde of the Green Dragon - Detective Comics #39 (1940): he kills a Chinese assassin. Later in the story he wipes out the Green Dragon Tong by crushing them beneath a giant statue
Wolf, the Crime Master - Batman #2 (1940): he breaks the neck of Adam Lamb (aka The Wolf) by punching him down a flight of stairs
The Crime School for Boys - Batman #3 (1940): he throws a criminal off a roof
The Strange Case of Professor Radium - Batman #8 (1940): he drowns Professor Radium
Professor Strange's Fear Dust - Detective Comics #46 (1940): he knocks Hugo Strange off a cliff. The Earth-Two Strange's death in this issue was later retconned during the Bronze Age, but this story marked his final fatal appearance during the Golden Age
Money Can't Buy Happiness - Detective Comics #47 (1941): he kills a gangster by knocking him out while he's driving and causing his car to crash headlong into a tree
The Brain Burglar - Detective Comics #55 (1941): he punches a foreign agent into a vat of molten steel. Later in the story he throws two more bad guys off a dirigible
The Two Futures - Batman #15 (1943): he kills some Japanese soldiers by throwing a bayonet into the tire of their car and causing it to crash. Later he crashes a plane into an Axis warship, killing everyone aboard
The Angel, the Rock and the Cowl - The Brave and the Bold #84 (1969): he destroys a German plane using a hand grenade. At the end of the story he uses dynamite to blow up a convoy of German soldiers as they are crossing a bridge
A Bat-Death for Batman! - Batman #221 (1970): he throws the villain Otto into a pit with frenzied animal that kills him
You Only Die Twice! - The Brave and the Bold #90 (1970): he knocks out a criminal and throws his unconscious body into the sea where he presumably drowns
Swamp Sinister - Batman #235 (1971): he punches Striss into a puddle of chemicals that infect him with a lethal disease
Vengeance for a Dead Man - Batman #240 (1972): he euthanizes Mason Sterling by deactivating the life support machine connected to his brain (Sterling tricked him into doing this)
The Menace of the Fiery Heads! - Batman #270 (1975): he punches Watkins into a statue, which then topples onto him and breaks his neck
The Corpse Came C.O.D. - Batman #271 (1976): he uses a sonically-charged amulet like a grenade to kill the Vedic cult leader and set fire to his temple while the cult members are still inside
Heart of a Vampire - Detective Comics #455 (1976): he shoots Gustav Decobra through the heart with a bow and arrow
Dead Man's Quadrangle - The Brave and the Bold #127 (1976): he ignores a criminal's mayday call, deducing it to be fake. It then transpires that the call was genuine, and the criminal has drowned as a result of Batman's inaction
Batman-Ex - - As in Extinct! - Batman #288 (1977): he uses a bad guy as a human shield by hurling him into the trajectory of the Penguin's gunfire, killing the man in the process
Skull Dugger's Killjoy Capers! - Batman #290 (1977): he electrocutes Dugger by throwing him into a nest of electrified cables
Time...My Dark Destiny! - The Brave and the Bold #157 (1979): he causes a helicopter to crash and the pilot is killed in the explosion
Where Walks a Snowman - Batman #337 (1981): he uses the flash of a marker flare to knock Klaus Kristin (aka. the Snowman) off a cliff.
The Crystal Armageddon! - The Brave and the Bold #159 (1980): he kills a member of the League of Assassins by throwing him against a wall made from a lethal formula, which then causes the assassin to turn to crystal and die. Batman knew this would happen and had actually warned someone against touching the wall earlier in the same scene
The Monster in the Mirror - Detective Comics #517 (1982): he kills Marley and drinks his blood
Those Who Live By The Sword - The Brave and the Bold #193 (1982): he stomach throws Bloodclaw off the Woodrow Wilson Bridge
The Messiah of the Crimson Sun - Batman Annual #8 (1982): he kills Ra's Al Ghul by drawing his spaceship into lethal sun rays
Night of Blood! - The Brave and the Bold #195 (1983): he stabs the vampire Gunnarson through the chest with a wooden table leg.
Batman: Year Two - Detective Comics #575-578 (1987): he takes Chill to Crime Alley, whereupon the Batman unmasks himself and reveals his true identity. He disarms Chill and turns the gunman's own weapon against him. Batman places the gun to Chill's forehead and is about to shoot him when suddenly the Reaper kills him first. Disappointed, Batman chases down and confronts the Reaper for the last time. At the end of the confrontation, the Reaper plummets to his death, taking the secret of Batman's true identity with him. But before he falls, he tells the Dark Knight "I didn?t think you were a killer? I see now I was wrong," implying that Batman would have killed Joe Chill had he not got to him first
Son of the Demon - (1987): he causes a helicopter crash that kills everyone on board. At the end of the story he kills Qayin by kicking him into some electric cables
Skeeter - Action Comics Annual #1 (1987): he stabs Skeeter through the back with a wooden stake
The Cult (1988): he guns down an innocent man during a hallucinogenic trance. Later he uses the Batmobile's armaments to demolish a building in orders to kill the rocket sniper on the rooftop. At the end of the story he cripples Deacon Blackfire and incites his follower's to turn on their leader. Robin tries to help Blackfire, but Batman stops him, then stands back and watches with a smile on his face as Blackfire is torn apart
Ten Nights of the Beast - Batman #420 (1988): he traps KGBeast in an underground chamber and leaves him to starve/suffocate
Consequences - Batman #425 (1988): he topples a pile of cars onto a villain, crushing him to death
Cosmic Odyssey (1988): he uses an Apokoliptian gun to blast a hole through the chest of one of Darkseid's soldiers
Shaman - Legends of the Dark Knight #1 (1989): Bruce Wayne accidentally knocks Tom Woodley off a mountain cliff. Woodley shows up alive and well many years later, but at this point Bruce believes his clumsiness has caused the death of a fellow human
Trash - Detective Comics #613 (1990): he kicks two bad guys into the back of a garbage truck and they are killed in the grinders
Succession - Detective Comics Annual #4 (1991): in vision of the future foreseen by Waverider, Batman kills Ra's al Ghul and later blows up himself and the entire League of Assassins, including Talia al Ghul
In the Dark Places - Batman #576 (2000): he kills a helicopter pilot by throwing a knife into the tail rotor of his helicopter and causing it to crash
All-Star Batman & Robin the Boy Wonder #1 (2005): he kills a group of corrupt policeman by ramming into their car with the Batmobile
All-Star Batman & Robin the Boy Wonder #2 (2005): he runs down several police motorcyclists and then incinerates a group of pursuing police vehicles using the rocket thrusters on the Batmobile
The Big Show - Detective Comics #814 (2006): he fights the army of madmen know as 'the Body', knocking several of them off rooftops and luring the rest to a building site where he has planted explosive charges. He then escapes via the Batwing, detonating the bombs as he goes and wiping out the madmen
The Beautiful People - Detective Comics #821 (2006): he knocks Johnny Lange in front of an oncoming train
All-Star Batman & Robin the Boy Wonder #7 (2007): he uses thermite and bleach to set fire to a gang, and continues to beat them up while they burn
Joe Chill in Hell - Batman #673 (2008): during an hallucinatory fantasy Batman hounds Joe Chill and drives him to the brink of suicide, then hands him a loaded gun and watches as he kills himself
Superman and Batman VS Vampires and Werewolves (2008-2009): he kills several vampires and werewolves in this series using stakes and a UV gun
How to Murder the Earth - Final Crisis #6 (2009): he uses an Apokalips gun to poison Darkseid
Bronze Night - Batman/Doc Savage #1 (2010): in this story Batman uses firearms in a cavalier manner and admits that he may be responsible for killing criminals
That's all I've got for now, but I'm sure there are plenty of other examples out there. Please add any you can think of.
