Men play an important role in transmission of human papillomavirus (HPV). Both in men and in women HPV causes great morbidity, such as cervical cancer, penile and anal cancer, and genital warts. The awareness of HPV and its consequences is essential to a successful vaccination program against HPV. In this study, we assessed awareness of HPV in Danish men. A random sample of men aged 18-45 years from the general male population was invited to participate in the study. The participants filled in a self-administered questionnaire with questions concerning awareness of HPV, lifestyle, and sexual habits. In the period from November 2006 to June 2007, more than 23 000 men were included in the study (participation rate approximately 71%). Overall, 10% of the participants reported to have heard of HPV. Comparison with an earlier study in Danish women showed lower awareness in men than in women (25%). Higher educational level and history of self-reported genital warts were the strongest predictors of having heard of HPV. Furthermore, condom use and excellent self-rated health were significantly correlated with awareness of HPV. In contrast, no correlations were found with age, lifetime number of sexual partners, and smoking and drinking patterns. In conclusion, we found that awareness of HPV among Danish men was scarce. The low level of awareness of HPV, particularly in men, can be a barrier in preventing HPV-related diseases. Education is warranted to increase such awareness to ensure success of HPV vaccination.