OBJECTIVES: The extended-release oxycodone hydrochloride is an opioid with similar action to morphine with proven efficacy in moderate to severe pain management. This study aims to develop a cost analysis of extended-release oxycodone versus morphine in an "if necessary" regime for cancer-related pain management, from the Brazilian public and private healthcare systems perspectives. METHODS: A decision model was developed to analyze the following strategies: group 1, 20 mg of extended-release oxycodone; group 2, 10 mg of extended-release oxycodone; and group 3, placebo. Efficacy data were obtained from Zhou e Wang, 2012. Direct costs were obtained from official price lists. Time horizon was determined through the hospital discharge period, and discount rates were not applied. Univariate sensitivity analysis was performed to evaluate different hospital categories.  RESULTS: Total costs were 1,103 BRL, 1,071 BRL and 1,214 BRL per patient treated, from the public perspective, in groups 1, 2 and 3, respectively. The addition of oxycodone (10 and 20 mg) to the treatment reduced hospitalization stay, leading to savings of up to 143 BRL per patient, or a 12% reduction in total hospitalization cost. Total costs were 2,372 BRL, 2,367 BRL and 2,759 BRL per patient treated, from the private perspective, in groups 1, 2 and 3, respectively. The addition of oxycodone to treatment can lead to savings of up to 392.66 BRL per patient, a reduction about 14% of the total treatment cost during hospitalization. The univariate sensitivity analysis showed consistent results.  CONCLUSIONS: The inclusion of extended-release oxycodone can lead to a reduction in total costs related to pain treatment in patients with cancer, which would lead to resource savings for the payer.