A simple, rapid and sensitive reverse phase high performance liquid chromatographic method has been developed for the determination of Mesalamine in bulk drug and pharmaceutical dosage forms. It was carried out using a mobile phase of methanol and 0.025 M potassium dihydrogen phosphate buffer (65:35 v/v) on a kromosil C18 column (250 X 4.6 mm, 5µm) in an isocratic mode at a flow rate of 1.0 ml/min. with detection at 250 nm using a UV detector. The linearity was obtained in the concentration range of 20 –100 µg/ml. The developed method was found to be accurate for the determination of Mesalamine in tablet dosage forms.