Rotational transitions of 16012C32S and 16013C32S in the ground vibrational state and of 16012C32S in several excited states have been accurately measured in the millimeter wave region for a minimum of four different J values. The analysis of the measured frequencies leads to rotational constants for the following vibrational states: 0 00 0 of 16O13C32S and 0 00 0, 0 1 1c 0, 0 1 1d 0, 0 20 0, 0 22c 0, 0 22d 0, 0 00 1 of 16O12C32S. Since the two components of the 0 22 0 transitions were resolved, an analysis of the l-type resonance was carried out and the interval 0 22 0 - 0 20 0 has been determined to be -4.63(10) cm-1. The result is in good agreement with the presently available determination of this level from vibrational spectra.