The genus Bothrops is one of the most important in America. The main clinical effects of envenoming by botropoid venoms are local tissue damage, life threatening bleeding and blood coagulation disorders, in addition to shock and renal failure. Currently, there are no reports from specimens of B. atrox in the Colombian Amazon. Therefore, this work aims to study the preliminary protein composition, morphometric characteristics and toxicity of B. atrox venoms from specimens belonging to the Caquetá Colombian department. The results showed no differences between the morphometrical parameters of male and female snakes, meanwhile, the protein composition showed an absence of a protein fractions between 91-100 and 111-120 KDa in male specimens, which are present in females with a relative abundance, the median lethal dose found was 63.8 μg/mouse, which are in accordance with others snake venoms found in Peru, but are lower than others species like Crotalusdurissuscumanensis, M. mipartitus and M. dumerilii.