  The Canada-France Brown Dwarf Survey is a wide eld survey for cool brown
dwarfs conducted with the MegaCam camera on the CFHT telescope. Our objectives
are to nd ultracool brown dwarfs and to constrain the eld brown dwarf mass
function from a large and homogeneous sample of L and T dwarfs. We identify
candidates in CFHT/Megacam i' and z' images and follow them up with pointed NIR
imaging on several telescopes. Our survey has to date found 50 T dwarfs
candidates and 170 L or late M dwarf candidates drawn from a larger sample of
1300 candidates with typical ultracool dwarfs i'-z' colours, found in 900
square degrees. We currently have completed the NIR follow-up on a large part
of the survey for all candidates from the latest T dwarfs known to the late L
color range. This allows us to build on a complete and well de ned sample of
ultracool dwarfs to investigate the luminosity function of eld L and T dwarfs.
