Furosemide is a loop diuretic that has been administered intravenously for years; however, its chemical stability has been determined only at dilute concentrations. The stability of furosemide diluted with 0.9% sodium chloride injection, and stored at either 22 deg C or 6 deg C in minibags (60, 120, and 160mg/50mL) and polypropylene stringes (10, 20, 40, and 80mg/10mL) and protected from light was studied. Samples were collected in triplicate on days 0, 3, 7, 14, 28, 56, and 84 and then after exposure to fluorescent light for an additional 7 days at 22 deg C. All samples were analyzed in duplicate by means of a stability-indicating high-pressure liquid chromatographic assay. Samples were also monitored for color, clarity, and changes in pH. All samples remained clear and colorless during the study period. The pH of the solutions did not change significantly during the study. All analyzed samples were stable for 84 days at 22 deg C or 6 deg C when protected from light and for an additional 7 days at 22 deg C when exposed to fluorescent light.