Objectives: to identify the main causes for hospital admissions and deaths related to systemic arterial hypertension and diabetes mellitus (DM), and to analyze morbidity and mortality trends, in a municipality in São Paulo's countryside, by comparing two three-years periods, 2002 to 2004 and 2010 to 2012. Methods: cross-sectional study which used secondary data regarding deaths from the Information System on Mortality and concerning hospital admissions from the DataSus Hospital Information System. Univariate and multivariate statistical analyses were conducted. Results: from 2002 to 2012, 325,439 people were admitted to hospitals, 14.7% of them due to circulatory system diseases (CSD) and 0.7% due to DM. The deaths distributed as the following: 29,027 deaths (31.5%) were due to CSD; 8.06% due to cerebrovascular diseases (CVD); and 2.75% due to DM. There was a significant association between admittance and death causes and patients' gender and age in the three-year periods (p<0.001). The highest lethality in hospital admissions was found to be due to CVD (10%). That trend showed that mortality rates dropped, younger patients were admitted due to DM, and older patients were admitted due to CVD - they were more often females. Conclusion: the main causes for hospital admissions were the CSDs; main mortality causes were the CVDs in hypertensive and diabetic women. Those findings can back public policies which prioritize the promotion of health.