Canadian Citizenship

You may become a Canadian citizen after you stay in Canada for three years. You may apply for the Canadian citizenship after 3 years of physical residence in Canada. Time spent outside of Canada beyond what may be expected for vacations, etc. may not be added.
If you have been living in Canada for three years or more as a permanent resident, you should consider becoming a Canadian citizen. If you were born in Canada, you are already a Canadian citizen.

What are the requirements?
If you are an adult, you must:

be 18 years of age or more
be a permanent resident of Canada
have lived in Canada for at least three of the four years before applying
be able to communicate in English or French
demonstrate knowledge about Canada and the rights and responsibilities of citizenship

A child must:

be a permanent resident of Canada (three year residency requirement not necessary)
Every applicant must complete an application form (parents can complete the form for their children). Every adult between the ages of 18 and 59 must pass a citizenship test, to demonstrate knowledge of English or French and about Canada.
Adults and children over the age of 14 must take the Oath of Citizenship.

You cannot become a Canadian citizen if:

You are or were in prison, on parole or on probation in the past four years.
you were convicted of an indictable crime in the past three years; or
you have been charged with a crime -- an indictable offence;
you are under a deportation order and are not allowed to be in Canada now;
you are now charged with an offence under the Citizenship Act;
you are under investigation for a war crime or a crime against humanity; or
Your Canadian citizenship has been taken away (revoked) in the past five years.