Ketoconazole is an imidazole anti – fungal agent. It interferes with the fungal synthesis of ergosterol, a constituent of cell membranes. Ketoconazole has wide spectrum antimycotic activity, but this compound is practically insoluble in water. The improvement of solubility increases bioavailability and therapeutical effects. In this paper, the influence of chosen solubilizers and co - solvents on the aqueous solubility of ketoconazole was investigated. The solubilizing effect of ethanol, propylene glycol, combination of ethanol (30%) and propylene glycol (10%), Tween 60, Tween 80 and SDS was studied. HPLC method was used for the solublility assay of the ketoconazole.