Dear vivi, all canadian citizens must file taxes, its just a NIL RETURN, which means 0 $ return, you can still do it, simply go to an accountant, say i didnt work , here is my sin number and thats it, i spent MOST of 2010 in iran , when i came back it was july, i went to an accountant and told them file my taxes, it took 2 mins, 0 0 0 0 , 0 return haha, 2 weeks later i called Revenue agency, i got my option c printout, which like i said was 0 and thats it ! you can still do it now , the MAIN reason for the tax return is to prove to them that listen i want to live here, not how much money you claim ! and when they approved your file it means they understand you being here for 5 months you are going to have a 0 return anyway so option c isnt needed, and when you get your RQ you can do the same and explain, or just file your tax before you get the RQ, they contact the revenue agency anyway so its no big deal