4 insecticidal carbamates: 3-methyl, 5-isopropylphenyl N-methyl-carbamate (Promecarb), 4-methylthio, 3,5 dimethylphenyl N-methylcarbamate (Mesurol), 4-dimethyl-amino, 3,5 dimethylphenyl N-methylcarbamate (Zectran), and 4-benzothienyl N-methyl-carbamate (Mobam) were orally administered to male Wistar rats. The excretion of the unchanged products was followed in 24 hrs urine collections. The corresponding phenols of the different carbamates could be identified as metabolites by gas-chromatography-mass spectrometyr. These metabolites were quantified afterward by gas-liquid chromatography. In all cases only minor quantities of unchanged products and metabolites were excreted in the urine over the 48 hrs after administration.