A spectrophotometric determination of iridium(M) is studied using o-methylphenyl thiourea (OMPT). Trivalent " iridium has been determined spectrophotometrically as its 1:1 [iridium(111):OMPT] complex in aqueous hydrochloric acid media (0.6 M). The complex exhibits maximum absorption from 512 nm to 522 nm with molar absorptivity 0.663 x 10(3) L mol(-1) cm(-1) and sandell's sensitivity 0.289 mu g of iridium(III) cm-2; beer's law is obeyed up to 300 mu g/mL. The relative standard deviation for ten replicate samples at 40 ug/mL level of iridium(III) is found to be 0.54 and the limit of detection of the method is 0.018 mu g/mL. Iridium(H)-OMPT complex is found stable for more than 8 days.