http://www.wpclipart.com/American_History/civil_war/Antietam/Antietam_sunken_road_1.png.html
Antietam Casualties:
Union: Confederate: Total:
Killed- 2,100 Killed- 1,550 Killed- 3,650
Wounded- 9,550 Wounded- 9,550 Wounded- 17,300
Missing/Captured- 750 Missing/Captured- 1,020 Missing/Captured- 1,770
Total Union Casualties:12,400
Total Confederate Casualties: 10,320
Total Battle Casualties: 22,720
(Actual numbers were impossible to compile based on the bloody nature of the battle. These are the best estimates from The Official Records of the War of the Rebellion and the Antietam Battlefield Board.)
http://www.nps.gov/anti/historyculture/casualties.htm