The present invention provides a pharmaceutical composition capable of forming in situ implant comprising goserelin or its pharmaceutically acceptable salts thereof biodegradable polymer and a biocompatible organic solvent wherein the biocompatible organic solvent is miscible to dispersible in aqueous medium or body fluid. The present invention further provides a process for the preparation of pharmaceutical composition capable of forming in situ implant. A kit containing composition for in situ implant is provided comprising a first vial comprising a composition comprising a biodegradable polymer and a biocompatible organic solvent wherein the biocompatible organic solvent is miscible to dispersible in aqueous medium or body fluid and a second vial comprising goserelin acetate.
