Thiosemicarbazones with their good chelatogenic properties and varied antimicrobial activities are thought of producing potentially beneficial molecules when derived from isatin for pharmaceutical applications. studies were initiated to complex Au(III) with N4 substituted thiosemicarbazones derived from isatin. the synthesis, spectral investigations and biolological activity of Au(III) Isatin N4substituted thiosemicarbazone complexes. The synthesized compounds were evaluated for antimicrobial activity against several gram negative and gram positivebacterium strains