Abstract： Objective To investigate the prevalence and pattern of androgenetic alopecia (AGA) in Shanghai through a community-based survey. Methods A cluster sampling survey was done among the residents in Beixinjing Community, Changning District, Shanghai. All the subjects were asked to fill a questionnaire to provide their general information, including sex, age, native place, physical status, life habit, family history, etc. The diagnosis of AGA was made by dermatologists. To determine the pattern of hair loss,Norwood-Hamilton classification system and Ludwig classification system were used for male AGA and female AGA, respectively. All the data were statistically analyzed by EpiData and SPSS11.5 software. Results Totally, 7056 subjects completed the questionnaire, including 3519 males and 3537 females, and the response rate was 72.5%. AGA was diagnosed in 809 patients, consisting of 701 males aging from 19 to 91 years (mean 64.16±11.9 years) and 108 females aging from 35 to 91 years (mean 70.46±18.89 years). The standardized prevalence (SP) was 9.47% in total, 15.73% in males and 2.73% in females; the difference was significant between males and females (χ2=356.00, P<0.001). A family history of AGA was observed in 52.7% of all subjects including 391 (55.78%) males and 35 (32.41%) females. Type Ⅲ vertex involvement was the most common type in men aging from 20 to 70 years old, and type Ⅵ in those over 70 years old. Grade Ⅰ and Ⅱ predominated in female AGA. Conclusions The results of this survey indicate that the prevalence of AGA is remarkably higher in men than that in women. Furthermore, the prevalence is steadily increased with advancing age in Shanghai.