Are Sigma lens compatible with a Canon DSLR?

I have my moms old Nikon film camera- slr. I'm going to get the Canon T2i with the kit lens, was wondering if the older Sigma lens will still work with a Canon camera?

Every camera company has their own mount. If the sigma lenses you are talking about fit the Nikon, they will NOT fit the T2i. Likewise if you get any EF or EF-S lenses from canon, they will not fit anything but Canon.

for your T2i, stick with canon lenses

Lens from another Mfg will not work on the Canon. The lens mounts are made & patented specific for each camera brand.

Ya, its compatible.

Sigma lens are compatible with a Canon DSLR you can go ahead for your stuff.

If those older Sigma lenses you refer to were for the Nikon then NO they will not fit the Canon. Sigma are a manufacturer that make lenses for all major camera brands, but they come in different 'mounts'.

A Sigma lens made for a Nikon will not fit a Canon. If you want Sigma lenses, then you have to buy Canon-mount versions.