An isocratic RP-HPLC-UV method for analysis of sumatriptan succinate in pharmaceutical dosage forms has been developed and validated. Best separation was achieved on a Thermo Hypersil C4 column (250 mm × 4.6 mm, 5 µm) using a mobile phase of 20 mM potassium dihydrogen phosphate adjusted to pH 4.0 with orthophosphoric acid and acetonitrile (65:35, v/v) at a flow rate of 1.0 mL min −1. UV detection was performed at 227 nm. The method was validated for specificity, linearity, precision, accuracy, limit of quantification, limit of detection, robustness, and solution stability. The calibration plot was linear over the concentration range 25–600 ng mL −1 ( r 2 = 0.9998) and the limits of detection and quantification were 10 and 25 ng mL −1, respectively. Intra-day and inter-day precision and accuracy were between 1.25 and 2.95% and between −1.15 and 2.47%, respectively. The method was successfully used for analysis of sumatriptan succinate, in the presence of excipients, in orally disintegrating tablets prepared in our laboratory and in commercially available tablets (Imigran) and nasal spray (Suminat).