This study presents Carbosulfan determination by a novel , robustic , mobile, inexpensive, and sensitive spectrophotometric method is developed for the determination of the carbamate pesticide carbosulfan in water and grains . An extractive method, which is based on alkaline hydrolysis of carbosulfan into phenol followed by coupling with diazotized 4- methyl aniline in alkaline medium. Yellowed coloured species (λ max 475 nm) can be extractable in to chloroform, which make reaction more sensitive with same λ max ..Beer’s law is obeyed over concentration range of 0.5-10μg/ml. Molar absorptivity and Sandell’s sensitivity were found to be 2.292 x 104 l mol-1cm-1 and 0.0166 μg cm-2 respectively. Method has been satisfactory applied for carbosulfan in various environmental samples.