An extensive literature search was performed using the key words squamous cell carcinoma of the penis, phimosis, circumcision, chronic balanitis, cigarette smoking, genital warts and human papillomavirus (HPV) infection. All selected studies were classified according to the level of evidence (LE). The final grades of recommendation were assigned after discussion by the full panel of the International Consultation on Penile Cancer in November 2008. The factors positively associated with invasive penile cancers include the presence of phimosis (LE 3a), tobacco smoking (LE 3a-4), chewing tobacco (LE 3a), injury to the penis (LE 3a), balanitis (LE 3a), genital warts (LE 3a), and high-risk HPV infection (LE 3a-4).