Objective: Increasingly, patients seek medical information via the Internet, despite highly variable information quality. We sought to determine whether controversial urological topics are associated with decreased content quality or search characteristics. Methods: We systematically searched the Internet for 5 noncontroversial (cryptorchidism, testicular torsion, urethral stricture, testicular cancers, renal cancers) and 5 controversial (disorders of sexual differentiation, circumcision, penile elongation, interstitial cystitis, testosterone therapy) conditions. Number of total hits, sponsored links, page owner and author, accreditation, updates, advertising, readability, and content quality were assessed for each topic. Content quality was determined on a 5-point scale for accuracy and completeness of 3 domains: diagnosis, natural history and treatment. Results: In total, 100 websites were evaluated. Noncontroversial topics had more hits (1,610,000 vs 475,000) and more sponsored links (30% vs 10%) than controversial topics. Noncontroversial web pages were more likely to have government or medical owners (58% vs 30%, P = 0.009) than controversial web pages. Website quality was significantly different between noncontroversial and controversial topics. In regard to accuracy, noncontroversial topics had higher scores for diagnosis (4.6 vs 3.8, P less than 0.0001), natural history (4.5 vs 3.2, P less than 0.0001), and treatment (4.6 vs 3.3, P less than 0.0001). Similarly, noncontroversial topics had higher completeness scores for diagnosis (3.8 vs 3.0, P = 0.001), natural history (3.7 vs 3.0, P = 0.003) and treatment (3.6 vs 3.0, P = 0.006). Conclusions: Web pages dedicated to controversial urological topics have lower quality content in regard to diagnosis, natural history and treatment. Such quality issues may contribute to ongoing public confusion and misinformation regarding these challenging topics. See also related editorial by J wan, p.1056-1057.