The biophysical interactions between the human serum albumin HSA and three synthesized diazo dyes 1-3 have been investigated by thermodynamic parameters and molecular docking technique. The binding constants Kb were calculated and the compounds were ranked according to their docking free energy. Different interactions were elucidated at the active site of the protein. Among these interactions is the hydrogen bonding which plays an essential role in the interaction with the protein. Both the theoretical and practical studies have agreed that diazo dye 1 has the strongest interaction with the active site.