A simple and sensitive spectrophotometric method has been developed for the determination of valacyclovir in bulk and tablet dosage forms. The method was based on the charge transfer reactions of Valacyclovir with 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone. The absorbance of the highly intensive coloured solution was measured at 450 nm against reagent blank treated similarly. Beer’s law is obeyed in the concentration range of 20-100 μg/ml. Statistical analysis proves that the proposed method is reproducible and selective for the routine analysis of pharmaceutical formulations of Valacyclovir.