A simple and sensitive visible spectrophotometric method for the assay of Picloram has been developed. In this method describe the interaction of Picloram, with the oxidative coupling reaction of Picloram with 3-methyl-2- benzothiazolinone hydrazone hydrochloride (MBTH) in presence of ferric chloride in an acidic medium, which results in a green colored product with absorption maxima at 625 nm. Regression analysis of Beer's law plot showed good correlation in the concentration range of 10-60 μgml-1. Different variables affecting the reaction were studied and optimized. The proposed method was applied successfully for the analysis of Picloram in its technical grade, chemical mixtures and environment samples. No interference was observed from common chemical mixtures and environment samples.