Research findings on comorbidity and pathological gambling are non–existent in Chinese communities. The objectives of this study were to: (a) determine the prevalence of comorbid mood and adjustment disorders among pathological gamblers seeking treatment in Hong Kong; (b) compare demographic profiles and clinical features in pathological gamblers with and without comorbid mood and adjustment disorders; and (c) explore the association and temporal relationship between pathological gambling and comorbid mood and adjustment disorders. Assessment instruments included demographic data, BSI, SCID-I, ASI and LIFE-RIFT. Results showed that about two-thirds (63.7%; n = 128) of 201 participants reported lifetime comorbid psychiatric disorders. Most common comorbid disorders were mood disorders (29.4%; n = 59) and adjustment disorders (20.9%; n = 42). Pathological gamblers with comorbid mood or adjustment disorders showed more severe levels of psychopathology, impairment in psychosocial functioning and gambling problems. This study is important because it is the first scientific comorbidity study among pathological gamblers in a Chinese context.