From the Facebook help page:

Facebook supports almost all video file types. Here's the complete list:


3g2 (Mobile Video)

3gp (Mobile Video)

3gpp (Mobile Video)

asf (Windows Media Video)

avi (AVI Video)

dat (MPEG Video)

divx (DIVX Video)

dv (DV Video)

f4v (Flash Video)

flv (Flash Video)

m2ts (M2TS Video)

m4v (MPEG-4 Video)

mkv (Matroska Format)

mod (MOD Video)

mov (QuickTime Movie)

mp4 (MPEG-4 Video)

mpe (MPEG Video)

mpeg (MPEG Video)

mpeg4 (MPEG-4 Video)

mpg (MPEG Video)

mts (AVCHD Video)

nsv (Nullsoft Video)

ogm (Ogg Media Format)

ogv (Ogg Video Format)

qt (QuickTime Movie)

tod (TOD Video)

ts (MPEG Transport Stream)

vob (DVD adult video)

wmv (Windows Media Video)

The aspect ratio of the video has to be between 9x16 and 16x9, and the video cannot exceed the file size or length that the upload page suggests.