OBJECTIVES: This study aimed to evaluate the impact of pneumonia, meningitis and sepsis and the how they represent the costs for patients 50 years and older in the Brazilian Private Health System. METHODS: An administrative claims database containing over 18 million lives was used to identify episodes of pneumonia, meningitis and sepsis, in all ages, between Oct/2010 and Dec/2013. The episodes were identified using ICD-10 codes of A40.3; B95.3; G00.1; J13; J15; J15.0; J15.3; J15.4; J15.8; J15.9; J18; J18.0; J18.9; J20.2 and P23.3 for pneumonia, A40; A40.0; A40.1; A40.8; A40.9; A41.8; A41.9; P36; P36.0 and P36.1 for sepsis, G00 and G00.9 for meningitis. Patients aged ≥50 years were identified and all-cause costs were extracted and grouped according to the 3 disease conditions. RESULTS: A total of 70,850 patients were identified (pneumonia: 68,717; sepsis: 1,745; meningitis: 388, representing 96.99%, 2.46% and 0.55% respectively). Different diseases disproportionately affected the populations. For pneumonia, 11.71% of episodes were in the ages 50+. Meningitis and sepsis represents 5.15% and 42.35%, respectively. The cost burden was also different by disease. Pneumonia had 56.95% of costs incurred by age 50+. For sepsis and meningitis, 75.8% and 15.53% of the costs were incurred by age 50+, respectively. CONCLUSIONS: Pneumonia, meningitis, and sepsis and its associated costs disproportionately affect the population in the Brazilian private health system. In particular, proportion of all pneumonia from patients age 50+ was only 11.71%, yet, the majority of expenditure (56.95%) for pneumonia patients is in the ages 50+. Pneumonia prevention strategies, including vaccinations, targeting adults age 50+, could potentially reduce healthcare costs associated with this condition.