Studies involving thermal analytical behavior, drug-excipient interaction and about polymorphism of Carvedilol (1-(9H-Carbazol-4-yloxy)-3-[[2-(2methoxyphenoxy)ethyl]amine]-2-propanol), a β-blocker drug, frequently applied in the heart diseases and ischemia treatment have been developed using thermoanalytical techniques Thermogravimetry (TG), derivative Thermogravimetry (DTG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC), with the aid of complimentary techniques infrared with Fourier transform spectroscopy (FTIR), powder X ray diffraction (P-XRD), scanning electron (SEM)and optical microscopies. Such studies revealed that carvedilol decomposes after melting releasing 2-methoxyphenol and ammonia in both nitrogen and air atmospheres. In inner atmosphere the decomposition took place as a single mass loss event without residue at the end, while in air, a first step resulted in carbonaceous residue that burnt completely in a second event. The DTA and DSC curves demonstrated that the sample melt around 100°C (∆H fus = 126,6 J g-1 , ∆S fus = 0,32 J K-1 g-1) without recristallyzation on cooling. An endothermic event observed previously to the melt has been attributed to a polymorphic conversion or the presence of racemates. Any interactions of the drug with excipients commonly used in the pharmaceutical industry such as: magnesium stearate, sacarose, PEG 6000, α-lactose monohydrate, hydroxypropyilmethylcellulose (HPMC), polyvinylpyrrolidone (PVP) and microcrystalline cellulose. Solid state decomposition kinetic investigation using the Flynn-Wall-Osawa approach revealed activation energy of E a = 243 ± 32 kJ mol-1 and Ahrrenius pré-exponential factor log A = 22 ± 3 min-1. Carvedilol recrystallization from different solvents and temperatures produced four kind of crystals: needles, prisms, superimposed plaques and plaques, attributed to the polymorphic forms II, III, IX and mixtures of forms III and IX respectively.