Compliance with chemotherapy in childhood leukaemia is usually good because of parental fear of the disease. However, poor compliance and refusal of treatment have been reported from both the USA and the UK. Little is known about African concepts of leukaemia, attitudes to treatment or compliance. A study was undertaken to investigate factors which might affect compliance in 15 black and 30 white families of leukaemic children in Johannesburg. The socio-economic and educational status of the black families was lower than that of the white. Only 53% of black children attended hospital on the appointed day compared with 90% of white children. Less than 50% of black parents understood the nature of their child's illness. Both black and white families had unused medication at home. White parents more frequently reported toxic effects related to chemotherapy and more white children than black children exhibited lymphopenia during maintenance therapy. Assessment of drug compliance should be included as an independent variable when evaluating factors affecting response to chemotherapy in communities of diverse ethnic, socio-economic and cultural backgrounds.