Biodegradable thermogelling copolymer hydrogels have great applicative potential in areas such as sustained drug release, gene delivery and tissue engineering. These injectable materials can be implanted in the human body with minimal surgical intervention. The thermosensitive copolymers have been incorporated with a variety of biocompatible and biodegradable components such as poly(D,L-lactic acid-co-glycolic acid), poly(L-lactic acid), poly (L-carprolactone), poly([R]-3-hydroxybutyrate), poly(organophosphazene), poly(peptide), poly(propylene fumarate), poly(propylene phosphate), polyacetal and poly(ortho ester). Various formulations consisting of the copolymers and therapeutic agents have been developed and the sustained release of these agents has been demonstrated. This review aims to provide a comprehensive summary of the recent developments in this field of study and highlights the most recent intellectual property and research papers.