The goal of Old Age Security is to provide a minimum income to Canadian citizens and legal residents aged 65 and older. OAS income is not dependent on your employment history and you do not have to be retired to begin collecting it. In fact, even if you have never worked in Canada, you can still receive OAS if you meet certain age and residency requirements. In general, the amount you receive is based on the length of time you have lived in Canada - the longer your residency, the larger the benefit.
If your income is above a certain amount, you may be required to repay some or all of the benefit you received.