Mental ill health forms an increasingly significant part of the burden of disease in developing countries. The growing interest in social risk factors for mental health coincides with the development of social capital research which may further inform the social model of mental health. The objective of the study reported here was to discover if there is an independent association between social capital and mental health when taking into account an array of demographic and violence variables. A total of 1168 youth (15-25 years) in a low income community in Cali, Colombia were surveyed. Mental health was measured by a 20 item self-report questionnaire. The instrument used to measure social capital covered structural and cognitive social capital. Twenty-four per cent of the sample were probable cases of mental ill health. Females had a prevalence rate three times higher than males. Using a model which considered demographic and social capital measures as potential risk factors for mental ill health, the significant risk factors emerged as being female, having limited schooling, working in the informal sector, being a migrant, and having low trust in people. The 'classic' poverty type variables (poor education and employment) were more important than social capital, as was the commonly dominant risk factor for mental ill health-being a woman. When violence factors were added to the model, the 'trust' factor fell out and the most important risk factors became (in descending order of importance): being female; no schooling/incomplete primary; and being a victim of violence. The dominance of poverty related factors, as opposed to social capital, prompts renewed attention to the explanatory mechanisms that link income inequality and poor mental health.