OBJECTIVES Invasive pneumococcal disease (IPD) is a major public health challenge. This study aims to perform a budget impact analysis (BIA) of 13-valent pneumococcal conjugated vaccine (PCV13) in adults immunocompromised (IC) or with comorbidities (CM), from a public payer perspective in Brazil. METHODS BIA using a Markov model framework estimated the incremental costs of a vaccination program over a 10 year period comparing PCV13 versus PPSV23 or no vaccination in adults ≥18 years with CM or IC. Population size was calculated from Brazilian Institute of Geography and Statistics (IBGE) projections for 2014-2023 period and prevalence of risk groups were extracted from literature. Efficacy data for PCV13 and PPSV23 were based on published data. Direct medical costs obtained from the literature included hospital days, medical fees, outpatient visits, diagnostic tests, and drugs in Brazilian Real (BRL). PCV13 and PPSV23 costs per dose were 52.40BRL and 23.00BRL, respectively.  RESULTS Eligible population consisted of 15,241,353 (CM) and 1,305,794 (IC) patients, for the 10-year period. After vaccination with PCV13, 111,869 (CM) and 42,786 (IC) IPD cases were avoided versus PPSV23 and 110,208 (CM) and 40,224 (IC) IPD cases versus no vaccination. Incremental costs per patient were 52.02BRL (CM), and 51.92BRL (IC), for vaccination with PCV13 versus non vaccination, leading to a budget impact of 793,005,843BRL (CM) and 67,805,835 (IC) for the 10-year period. For vaccination with PCV13 versus PPSV23, incremental costs per patient were 29.13BRL (CM) and 28.97BRL (IC) leading to a budget impact of 444,074,277BRL (CM) and 37,846,568BRL (IC) for the same period. CONCLUSIONS The addition of PCV13 to the immunization schedule in adults ≥18 years with comorbidities or immunocompromising condition would avoid more IPD cases, with an incremental cost varying from 37,846,568BRL to 793,005,843BRL over a 10 year period.