A spectrophotometric method for the determination of carbaryl in soil samples is described. The method is based on the coupling of 1-naphthol obtained from hydrolyzing carbaryl with diazotized sulphanilic add in an alkaline medium to form p-(4-hydroxyl-1-naphtylaza) benzenesulphonic acid which has a maximum absorbance at 475 nm. The results of analysed soil samples within a four day period ranged from 4.01 to 63.68 mg kg(-1) 1-naphthol at 0-3 an depths. The proposed method is sensitive and rapid. Average 1-naphthol content of the soil samples was 26.62 ppm.