Coevaporates of warfarin sodium containing different weight fractions of polyvinylpyrrolidone (Kollidon s5 and 30) polymers of different molecular weights were prepared and their characterization, dissolution properties as well as their bioavailability in rabbits were assessed. UV and IR spectrophotometery revealed a sort of binding between the drug and polymers. Optimum binding tendency appears at polymer weight fractions of 0.7 and 0.5 for Kollidon 25 and Kollidon 30, respectively. Incorporation of the drug with PVP enhances its dissolution properties and improves its bioavailability. Of all the investigated warfarin/PVP systems, the coevaporate of warfarin with an equal weight fraction of Kollidon 30 was found to exhibit optimum biological properties beside highest dissolution rate.