Objective to analyze the Primary Health Care nurses' practices for monitoring the four main Chronic Non-communicable Diseases (circulatory system diseases, cancer, diabetes, and chronic respiratory diseases) in a city in the interior of Santa Catarina State. Method single case study, qualitative approach. Data was collected through triangulation of techniques: focused interviews, document analysis, and online database, from January to July 2019. The analysis techniques were given by means of theoretical propositions and the construction of explanation regarding the nurses' practices. Results the nurse's practices for monitoring chronic diseases identified were: HiperDia Group; health education; tele-monitoring; welcoming; home visits; nursing consultation; care plan; self-monitoring and protocols. Conclusion and implications for the practice the nurses in the studied context perform several practices for the monitoring of chronic diseases, contributing to the effectiveness of policies for this condition and, possibly, with the drop in the mortality indicator for these causes.