The dissolution rates of a number of drug-urethan solid-state dispersion systems were studied. A marked enhancement of the initial dissolution rates of several poorly water-soluble drugs was found when they were incorporated into a urethan matrix by heat fusion. These differences were considerable when pure substances such as griseofulvin, hydrocortisone, chloramphenicol, and acetaminophen were compared to the urethan-drug solid dispersion. Physical mixtures of the medicinal agents with urethan also gave a marked increase in the amount of drug in solution, with the value in most cases being over one-half that of the solid-state dispersion. Data are given, comparing ultrafiltration with samples filtered through cotton, regarding drug content remaining in solution.