OBJECTIVES: Bevacizumab plus interferon-α2a (BEV+IFN) prolongs progression-free survival (PFS) to > 10 months, providing comparable efficacy to sunitinib in patients with metastatic renal cell carcinoma (mRCC). However, the type and frequency of adverse events (AE) differ between these two regimens. We aimed to assess the costs of managing AE of grade 3/4 of these regimens from the perspective of public health care system in Mexico. METHODS: A linear decision analytic model was developed to compare the direct medical costs of managing AE of grade 3/4 of BEV+IFN and sunitinib in patients with mRCC. AE of grade 1/2 are assumed to entail very low costs or even no medical attention and therefore were not taken into account. Data sources included the published incidence rates for the 25 most frequent AE in controlled clinical trials with BEV+IFN or sunitinib. A panel integrated by 10 local experts from different specialties was constituted to estimate medical and non-medical resource use for diagnosis and treatment of each AE grade 3/4. Cost of medications involved in treating AE were taken from public bids and unit cost of medical services (outpatient medical consultations, laboratory and image tests, hospitalization at general ward and at intensive care unit, surgical and non-surgical procedures, etc.) were gathered from official tariff lists. All costs are expressed in 2009 Mexican Pesos (MXN). RESULTS: The average cost per patient for the management of grade 3/4 AE were 76.5% higher for sunitinib ($17,577) than those for BEV+IFN ($9,959). The main cost drivers for sunitinib were hypertension, hearth failure and non-febrile neutropenia; for BEV+IFN, main cost drivers included proteinuria and arterial and venous thromboembolic events. CONCLUSIONS: BEV+IFN has a more tolerable AE profile when compared to sunitinib, which is also reflected in the nearly double cost for managing AE with sunitinib in patients with mRCC.