The aims of this study were to analyze unnecessary laboratory exams for patients with hypertension and diabetes and to check the expenditures involved. This is an exploratory-descriptive, cross-sectional study with a quantitative approach. We used data from medical records of 293 patients registered in primary units - the Family Health Center (NSF3); secondary: School Health Center (CSE); and tertiary: Hospital das Clínicas (HC) from 2006 to 2009 in a city in Southeastern Brazil. We identified a total of 9,522 laboratory tests, of which 5.97% were unnecessary. Of these, about 58% were requested by NSF3 and 42% by CSE. Results suggest there is a lack of integration among different levels of health care, which result in misallocation of resources and unnecessary spending.