Purpose: Data on mental disorder prevalence and health service utilization required to inform healthcare management and planning are lacking in Hong Kong. The current study determined the prevalence of common mental disorders (CMD), and examined the patterns of mental health service utilization and associated factors. Methods: We analyzed data from the Hong Kong Mental Morbidity Survey (HKMMS) of 5,719 Chinese adults aged 16–75 years in the general Hong Kong population, using the Chinese Revised Clinical Interview Schedule (CIS-R). Results: The weighted prevalence estimate for any past-week CMD was 13.3 %, with mixed anxiety and depressive disorder being the most frequent diagnoses. CMD was positively associated with female gender, being divorced or separated, alcohol misuse, substance dependence, lack of regular physical exercise, and a family history of mental disorder. Among individuals with CMD, only 26 % had consulted mental health services in the past year; less than 10 % consulted general practitioners or family physicians. Lack of mental health service usage was significantly more likely in men and those with lower educational attainment. Conclusions: Apart from attention to psychosocial risks, health and lifestyle factors are important considerations for mental health promotion. Service utilization for individuals with CMD in Hong Kong remains suboptimal, and would be enhanced by strengthening community primary care. © 2015, Springer-Verlag Berlin Heidelberg.