A sensitive and selective RP-HPLC method was developed and validated for the quantitative determination of trimazolin hydrochloride in nasal drops formulations. The mobile phase composition was water-acetonitrile (50:50, v/v) and the UV detection was carried out at 270 nm. Linearity range in the concentration range of 10 to 110 ?g cm-3. The method was tested and validated for various parameters according to ICH guidelines. The detection and quantization limits were found to be 1.45 and 4.8 ?g cm-3, respectively. The results demonstrated that the procedure for estimation of trimazolin hydrochloride in nasal drops formulations was accurate, precise and reproducible.