BACKGROUND: It had been claimed that stigma and social distance are less severe in African countries, although not enough research had been done to confirm this. Most of the studies had focussed on the general community, and specific population groups had been neglected. AIMS: The aims of this study are to examine the level of social distance of students in a Nigerian university towards people with mental illness and to assess the possible socio-demographic variables involved. This is to enable the development of appropriate mental health educational and stigma-reducing programmes. METHODS: A modified version of Bogardus Social Distance Scale was used to assess the desire for social distance towards people with mental illness amongst 1,668 students of a Nigerian federal university. Socio-demographic details were also obtained. RESULTS: The social distances increased with the level of intimacy required in the relationship and were higher than those from the western culture, with 65.1% of the respondents categorised as having high social distance towards the mentally ill people. The predictors of high social distance towards the mentally ill include female gender [odds ratio (OR) 2.09, 95% confidence interval (CI) 1.69-2.60], studying a non-medical course (OR 4.65, 95% CI 3.01-7.19) and not having a family member with mental illness (OR 6.73, 95% CI 4.34-10.44). CONCLUSION: Social distance towards the mentally ill is higher amongst Nigerian university students than expected. This challenges the notion that stigma and negative attitude towards the mentally ill are less severe in Africa than in western cultures. There are needs for intensive public awareness, effective stigma-reducing educational programmes and more research in this area.