OBJECTIVES: To assess the quality of private pharmacy practice with a focus on the extent of antibiotic sales without prescription in private pharmacies in four Zimbabwean cities in relation to two tracer infectious conditions-sexually transmitted infections (STIs) among females and males, and diarrhoea in a child. METHODS: A cross-sectional study including pharmacies in Harare and three other towns. Information about each pharmacy was collected through structured interviews. Staff were interviewed using a different structured interview guide and simulated clients were used to assess staff performance. Data were analysed statistically, and step models to evaluate pharmacist performance were developed. RESULTS: A majority (69%) stated that they would never sell an antibiotic without a prescription and very few actually did in spite of a high patient demand. Few respondents however performed acceptably regarding provision of information and advice in relation to guidelines: 8% for the STI male, 33% for the STI female and 22% for the diarrhoea scenario. CONCLUSIONS: The study revealed low sales of antibiotics without prescription, showing good adherence to the letter of the law. However, few respondents performed acceptably in relation to guidelines when considering information and advice for the tracer conditions.