The photodissociation of dimethylsulfoxide [(CH3)(2)SO] at 193.3 nm has been investigated using the molecular beam time-of-flight (TOF) mass spectrometric technique. in addition to CH3 and SO, CH3SO is also observed as a stable primary product, indicating that CH3SO+CH3 is an important 3 product channel for the 193.3 nm photodissociation of (CH3)(2)SO. The analysis of the TOF data provides evidence that SO is formed via a stepwise mechanism : (CH3)(2)SO+hv (193.3 nm) --> CH3SO+CH3-->2CH(3) + SO. The analysis also indicates that approximate to 53% of the primary CH3SO radicals undergo further dissociation to produce CH3+SO, yielding a quantum yield of approximate to 1.53 for CH3. Within the sensitivity of our experiment, the product channel of CH3SCH3 + O is not found. The angular distribution for the formation of CH3SO + CH3 is found to be isotropic, an observation consistent with a predissociation mechanism, in which the dissociation of photoexcited (CH3)(2)SO is slow compared to its rotational period. The energetics for selected dissociation reactions of (CH3)(2)SO have also been investigated by ab initio calculations at the G2(MP2) level of theory. The experimental dissociation energy at 0 K (53 +/- 2 kcal/mol) for the CH3-SOCH3 bond obtained here is in excellent agreement with the theoretical prediction of 52.6 kcal/mol.