Objectives: The purpose of this study was to develop a simple and cost-effective method for the determination of urinary 4,4′-methylenebis (2-chloroaniline) (MBOCA) by gas chromatography-electron capture detection (GC-ECD) for biological monitoring of occupational exposure to MBOCA. Methods: MBOCA was prepared by liquid-liquid extraction after alkaline hydrolysis, derivatized with N -methyl-bis (trifluoroacetamide) and then analyzed using GC-ECD. The proposed method was validated in accordance with the US Food and Drug Administration guidance. Results: The calibration curve showed linearity in the range 1–100 µ g/l, with a correlation coefficient of >0.999. The limits of detection and quantification were 0.3 µ g/l and 1 µ g/l, respectively. The recovery was 94–99%. Intraday accuracy, expressed as the deviation from the nominal value, was 90.5–100.3%, and intraday precision, expressed as the relative standard deviation, was 0.3–2.4%. Interday accuracy and precision were 87.8–100.2% and 0.3–4.1%, respectively. Conclusions: The proposed method is a simple and cost-effective method suitable for routine analyses and could be useful for biological monitoring of occupational exposure to MBOCA.(J Occup Health 2014; 56: 347-350)