2-Thiothiazolidine-4-carboxylic acid (TTCA) is the accepted urinary indicator of occupational exposure to carbon disulfide. An extractionless automated column-switching procedure for the determination of this compound in urine was developed. The biological fluid is directly injected into the chromatographic system after dilution. A clean-up procedure is performed in an anion-exchange pre-column, with aqueous formic acid as eluent, followed by a transfer to a cyan-amino or amino analytical column in order to carry out analysis of TTCA under isocratic elution conditions, with a mixture of acetonitrile, water and formic acid as eluent, combined with ultraviolet detection. The detection limit of the method in urine is estimated to be 0.1 mg/l.