Objective: To investigate underlying causes for food and nutrition insecurity in black South African households and to gain understanding of the factors contributing to better nutrition security, with emphasis on household organisation, gender and intrahousehold dynamics and social networks. Design, setting and subjects: Within a larger cross-sectional survey that investigated the impact of urbanisation on the health of black South Africans, 166 people, mostly women, were interviewed on household food security. Methods used were structured face-to-face interviews, in-depth interviews, observation, interviews with key informants and a sociodemographic questionnaire. Information was collected from 1998 to 2000 in 15 rural and urban areas of the North West Province, South Africa. Results: Three-quarters of households in this sample are chronically food-insecure. Families are disrupted, due to migrant work, poverty and increasing societal violence, and half of households are female-headed. Certain categories of female-headed households and households based on partnership relationships, despite more limited resources, achieve a better or an equal economic status and better nutrition security than those households led by men, with the latter often being considered an economic liability. The reliance on and fostering of social ties and networks appear to be of central significance. Conclusion: Gender and intra-household relations, as well as social networks and income from informal sector activities, are often not uncovered by conventional statistical methods. Qualitative research can reveal the unexpected and furthermore empowers people, as their voices are heard.