OBJECTIVES: Cancer patients are susceptible to infections, including pneumonia, due to immunosuppressive therapies associated with cancer treatment.  This study aimed to evaluate the budget impact of pneumonia in patients with previous diagnosed cancer in the Brazilian Private Health System. METHODS: Orizon database (N=18 million lives) was used to identify patients with any type of cancer followed by a pneumonia hospitalization between October 2010 and December 2013.  Pneumonia was identified using code 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, P23.3. Inpatient and related outpatient costs were included. RESULTS: A total of 68,717 patients with a pneumonia hospitalization were identified. Of those, 2,769 were diagnosed with cancer (WCa) before the pneumonia hospitalization for a total of 3,605 hospitalizations. This translated to a mean of 1.30 hospitalization per WCa patient. The group without cancer diagnosis (WoCa),65,948 pneumonia patients had a total of 81,583 hospitalizations for a mean of 1.24 hospitalizations. The average costs per patient are BRL2,863.08 for the WoCa group and BRL9,288.07 for the WCa group. When considered the costs per hospitalizations the values are BRL2,314.60 and BRL7,134.16 respectively. CONCLUSIONS: Although the number of pneumonia hospitalization per patient was slightly higher in WCa compared with WoCA patients, the cost per patient and cost per hospitalization was at least 3 times higher in the WCa compared with WoCA patients. This suggests pneumonia has a substantial financial impact in patients with cancer who are in the Brazilian Private Health System.