Simultaneous thermogravimetry-differential scanning calorimetry (TG-DSC) and coupled thermogravimetry-infrared spectroscopy (TG-FTIR) analyses were used to study the antihypertensive drug atenolol. The TG-DSC curves provided information concerning the thermal stability and decomposition profiles of the compound. From the TG-FTIR coupled techniques, it was possible to identify ammonia and isopropylamine as possible volatile compounds released during the thermal decomposition of the drug.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)