Parenteral delivery of the hydrophobic drugs is a very challenging task. The conventional approaches such as use of co-solvents, oily vehicles and modern approaches such as mixed micelles, liposomes, complexation with cyclodextrins and emulsions have several limitations. Microemulsions have evolved as a novel vehicle for parenteral delivery of the hydrophobic drugs. Their interesting features such as spontaneity of formation, ease of manufacture, high solubilization capacity and self-preserving property make them the vehicle of choice. The review focuses on the excipients available for formulation of the parenteral microemulsions and describes the investigations reported for the various classes of therapeutic agents.