The prevalence of HIV and HPV is high among men who have sex with men (MSM) in China. It is unclear whether cognitive and affective responses related to HPV and HPV-related diseases are negatively associated with HIV-related risk behaviors among MSM. This cross-sectional study interviewed 449 adult Chinese MSM in Hong Kong. The prevalence of unprotected anal intercourse (UAI) and having had anal sex with more than one man in the last 6 months (multiple male sex partnerships) was 39.0 and 71.3 %, respectively. After adjusting for four significant background variables (education level, cohabitation with a man, exposure to HIV prevention materials, and HIV voluntary counseling and testing), variables negatively associated with UAI and/or multiple male sex partnerships included (1) correct HPV-related knowledge (AOR = 0.48-0.66), (2) perceived susceptibility (AOR = 0.32-0.55) and perceived severity (AOR = 0.12-0.60) related to HPV and HPV-related diseases, and (3) fear towards contracting genital warts and penile/anal cancer (AOR = 0.40-0.55). Perceived high chance of contracting HPV was positively associated with multiple partnerships (AOR = 4.74). It is possible to reduce HIV-related risk behaviors by increasing levels of knowledge, cognitions, and fear related to HPV and related diseases. It is important to integrate prevention of HIV with prevention of sexually transmitted infections. Such interventions are warranted.