Background: Only 30-35% of people with mental health problems seek help from professionals. Informal help, usually from friends, family and religious leaders, is often sought but is under-researched. This study aimed to contrast patterns of informal and formal help-seeking using data from a community psychiatric morbidity survey (n=1692) (South East London Community Health (SELCOH) Study). Methods: Patterns of help-seeking were analysed by clinical, sociodemographic and socioeconomic indicators. Factors associated with informal and formal help-seeking were investigated using logistic regression. Cross-tabulations examined informal help-seeking patterns from different sources. Results: 'Cases' (n = 386) were participants who had scores of ≥ 12 on the Revised Clinical Interview Schedule (CIS-R), indicating a common mental disorder. Of these, 40.1% had sought formal help, (of whom three-quarters (29%) had also sought informal help), 33.6% had sought informal help only and only 26.3% had sought no help. When controlling for non-clinical variables, severity, depression, suicidal ideas, functioning and longstanding illnesses were associated with formal rather than informal help-seeking. Age and ethnic group influenced sources of informal help used. Younger people most frequently sought informal help only whereas older people tended to seek help from their family. There were ethnic group differences in whether help was sought from friends, family or religious leaders.