The stability of 9-[(1,3-dihydroxy-2-propoxymethyl]) guanine sodium (ganciclovir sodium, also known as DHPG sodium) in two infusion solutions was studied. Lyophilized ganciclovir sodium 500 mg was reconstituted with sterile water 10 mL to give a theoretical concentration of 50 mg/mL. After reconstitution, 6-mL aliquots of the solution were added to 100 mL of 0.9% sodium chloride injection or 5% dextrose injection in polyvinyl chloride i.v. bags. One sample was withdrawn from each of 10 bags of each solution and analyzed by high-performance liquid chromatography (HPLC). Thirty bags of each solution were then stored under each of the following conditions: at room temperature under laboratory light, at room temperature in the dark, and under refrigeration for up to five days. Single potency assays were performed by HPLC on each of three bags of solution at three and five days after initial dilution of the solutions. The solutions were visually inspected, and the pH of the solutions was measured. All solutions of ganciclovir were stable for at least five days under all storage conditions; mean ganciclovir concentrations did not drop below 98% of initial theoretical values throughout the storage period. No important changes in the pH of the solutions occurred during the study period. Under the conditions of this study, ganciclovir sodium is stable for up to five days when prepared in 5% dextrose injection or 0.9% sodium chloride injection.