This study developed an optimized preventive maintenance plan for three key technologies in clinical laboratories of the Sistema Provincial de Salud de Tucumán: hematological counters, clinical chemistry autoanalyzers and systems combined with reverse osmosis purification plants. The proposal was based on the analysis of the inventory, historical records of failures, technical consultations and review of manuals, applying the Fennigkoh and Smith model to classify criticality and prioritization. This made it possible to define thresholds for including equipment and establishing differentiated frequencies, considering local variables such as seasonal demand and geographical factors. Technological homogeneity facilitated the standardization of checklists for a program that contemplates 87 annual interventions distributed over 34 weeks. The institutional grouping strategy optimized the use of technical resources and minimized idle time, validating operational feasibility in terms of available human resources. It is emphasized that the plan should be dynamic, with periodic reviews to adjust the criticality and frequency according to the aging of the equipment, the demand and the incorporation of new technologies. In addition, it was identified that 68.8% of failures in hematology counters are attributed to operational errors, highlighting the need for continuous training. Finally, collaboration within the health system itself is essential to ensure the logistics and efficient operation of the plan. The plan’s design strategy can be replicated in other contexts, promoting sustainability, extending the useful life of the equipment, reducing costs and guaranteeing the quality and continuity of the diagnostic service.