To enhance the bioavailability of the poorly water-soluble drug Aceclofenac, a lipidnanoemulsion comprising ethanolic solution of phospholipid 90 G and tween 80 in 1:1 ratio (Smix), triacetin and anseed oil as oil phase and distilled water as aqueous phase, in the ratio of 55:15:30 (% w/w) was developed by constructing pseudo-ternary phase diagrams and evaluated for viscosity, % transmittance, and surface morphology of nanoemulsions. In vitro diffusion (release) of Aceclofenac from three different bases to an aqueous receptor phase through cellophane membrane was monitored spectrophotometrically at 273 nm. Compared with hydroalcoholic drug solution, oily solution, and conventional emulsion and suspension. The lipid-nanoemulsion showed increase in drug release compared to drug suspension. This may be attributed to increased solubility of the drug from nanosized emulsion.