Abstract: Mechanism of interaction between amphetamine (APTM) and bovine serum albumin (BSA) was studied by fluorospectroscopy. It was shown that fluorescence quenching of BSA was observed due to its reaction with APTM, and the fluorescence quenching process was attributed to static quenching. Number of binding sites (n) was found to be 2. On the basis of the force of interaction between the molecules and correlation among the thermodynamic parameters, as well as the fact that values of ΔH and ΔS of the interaction between APTM and BSA were all >0, it was deduced that the force of the reaction was mainly due to hydrophobic action. It was found by synchronous fluorospectroscopic study, that as a result of interaction between the 2 compounds, significant decrease of fluorescence intensity of BSA, and hypsochromic shift of characteristic peaks of tyrosin and tryptophan in BSA molecules were observed, leading to enhancement of hydrophobicity and decrease of hydrophilicity of the remaining radicals of amino acids, and it was also inferred that binding sites of APTM with BSA were located at the remaining radical of tryptophan.