Simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), differential scanning calorimetry (DSC) and coupled thermogravimetry coupled to infrared spectroscopy (TG-FTIR) were used to study the antihypertensive drug amlodipine besylate. The TG-DSC curves provided information concerning the thermal stability and the decomposition steps of the compound, while the DSC technique allowed us to confirm that the melting occurs concomitantly with the decomposition of the sample. By using the TG coupled to FTIR coupled techniques, it was possible to identify ammonia and methanol and CO2 as compounds released during the thermal degradation of the drug. ; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)