This book highlights enhancement of biovailability of poorly water soluble drugs by nanoemulsion technique. The preparation and characterization of nanoemulsion is discussed by spontaneous emulsification technique, which is an easy process to be carried out at lab scale. There was 2.87 fold increase in oral bioavailability compared to marketed tablets. Our studies illustrate the potential of lipid based nanoemulsions as useful drug delivery tool for BCS Class II drugs.