Men with prostate cancer are reported as commonly using complementary and alternative medicine (CAM) but surveys have not recently been subjected to a rigorous systematic review incorporating quality assessment. Six electronic databases were searched using pre-defined terms. Detailed information was extracted systematically from each relevant article. Study reporting quality was assessed using a quality assessment tool, which demonstrated acceptable inter-rater reliability and produces a percentage score. In all, 42 studies are reviewed. All were published in English between 1999 and 2009; 60% were conducted in the United States. The reporting quality was mixed (median score = 66%, range 23-94%). Significant heterogeneity precluded formal meta-analysis. In all, 39 studies covering 11,736 men reported overall prevalence of CAM use; this ranged from 8 to 90% (median=30%). In all, 10 studies reported prevalence of CAM use specifically for cancer care; this ranged from 8 to 50% (median = 30%). Some evidence suggested CAM use is more common in men with higher education/incomes and more severe disease. The prevalence of CAM use among men with prostate cancer varies greatly across studies. Future studies should use standardised and validated data collection techniques to reduce bias and enhance comparability.