Statistics for A simple, rapid, selective and sensitive spectrophotometric method for the determination of platinum has been proposed based on the colour reaction between platinum(IV) and piperonal thiosemicarbazone (PATS) in 0.008 - 0. 032 M sulphuric acid medium. The greenish yellow complex has an absorption maximum at 360 nm. Beer's law is obeyed upto 6.5 ppm of Pt and the optimum concentration range is 1 - 5.1 ppm of Pt. The molar absorptivity and Sandell's sensitivity are 3. 239 x 104 1 mol-1 cm-1 and 0.006 ?g cm-2, respectively. The optimum conditions for complete colour development have been investigated by studying parameters like effect of medium, acidity, reagent concentration, time period and effect of diverse ions. The method is used for the determination of platinum in hydrogenation catalysts and platinum complexes.