OBJECTIVES: Congestive heart failure (CHF) is an important medical, social and economical problem worldwide, and is associated to hard outcomes, such as death and hospitalization. This study analyzes economic impact in a health plan. METHODS: Observational case-control study involving 71,094 individuals attended by the health plan. From these, we selected a sample of 396 individuals diagnosed with CHF and, for each case, three controls with the same age and sex. We analyze the frequency of use of health services during 12 months (visits, tests, treatments, hospitalizations and readmission) by sex and age. The annual costs of health care were compared with the costs of individuals who were not diagnosed with CHF (ICD10-I50). Statistical analysis used OpenEpi software, by calculating the relative and absolute frequencies, means and standard deviation. For statistical significance, Chi-square tests (Mantel-Haenszel and Fisher's Exact), when p<0.001. RESULTS: Of the selected sample diagnosed with CHF, 54.3% were male, with a mean age of 72.8 years and 45.7% female, mean age 72.7 years. In this group, the utilization of health plan was significantly higher than individuals without CHF for tests (p<0.001, OR 1.64), hospitalizations (p<0.001; OR 6.72), readmission in less than 12 months (p<0.001; OR 6.59), long-term hospitalization (>30 days) (p<0.001; OR 6.54) and not significant in visits (p=0.163) and therapies (p=0.378). The annual expenditure was US$ 3,432.27 versus US$ 1,608.90 by patients who haven´t CHF (213.3% more). Considering the estimated prevalence and the incremental cost, the annual impact of disease for the health plan was US$ 6,714,872.34. CONCLUSIONS: As observed, the utilization of inpatient medical services from individuals with CHF was significant higher than group control, which represents more than 200% increase in total costs generated due to this component.