The widely used screening for prostate cancer with prostate specific antigen has resulted in identification of potentially lethal prostate cancers at a much more curable stage and has been associated with significant falls in prostate cancer mortality. In spite of the fact that prostate cancer is one of the deadliest malignancies in men, the advent of sensitive diagnostic testing has also resulted in detection of low risk cancers due to the high incidence of latent prostate cancer in aging men and prolonged natural history of the disease. This, in turn, has entailed the problem of cancer overdiagnosis and subsequent overtreatment. Approximately 6 times as many men will be diagnosed with the disease as will die from it. Active surveillance appeared as a response to the clearly documented risks of overdiagnosis and overtreatment of low risk prostate cancer for localized prostate cancer. It entails initial expectant management rather than immediate therapy, with 'curative-intent' treatment deferred until there is evidence that the patient is at an increased risk of disease progression. This approach attempts to balance the risks and side effects of overtreatment against the possibility of disease progression and lost opportunity for cure. A systematic literature review brings current knowledge on the subject.