ABSTRACT Objective: to describe the knowledge of nurses on Health-Care Waste Management (HCW) in Family Health Units (FHU) of São Carlos city, São Paulo State. Method: exploratory, descriptive and quantitative approach. The research was carried out with nurses of 16 FHU of the municipality of São Carlos-SP. Data were collected through an interview using a tool validated and analyzed using descriptive statistics. Results: it is noteworthy that 68.7% (11) of the nurses did not know how to describe how chemical waste was sorted. In addition, regarding the treatment of HCW, 50.0% (8) of the nurses did not know if the general waste were subjected to some type of treatment. Conclusion: the HCW management can be considered a challenge in the nurses' agenda inserted in the Primary Care services, which refers to the need to implement periodic training on the management of this waste.