The photodissociation dynamics of trimethylene sulfoxide (C3H6SO) has been studied by monitoring the nascent SO(X (3) Sigma(-)) photofragment following 193- and 248-nm irradiation by using laser-induced fluorescence spectroscopy on the B (3) Sigma(-)-X (3) Sigma(-) transition. Inverted vibrational-state distributions are observed, with maxima at upsilon " = 1, for the nascent SO(X (3) Sigma(-)) photoproduct for both photolysis wavelengths. Quantum yields for the production of SO(X (3) Sigma(-)) are 0.34 +/- 0.05 and 0.70 +/- 0.14 following 193- and 248-nm photolyses of C3H6SO. Rotational-state distributions of the nascent SO(X (3) Sigma(-), upsilon " = 1-5) photofragment have been measured following photolysis at both wavelengths and can be characterized by Boltzmann temperatures. Energy disposal into the internal degrees of freedom of the SO(X (3) Sigma(-)) photofragment is 9.9% and 11.3% of the total available energy following irradiation of the parent molecule at 193 and 248 nm, respectively. Franck-Condon and impulsive models have been used as limiting cases for the experimentally observed vibrational-state distributions and the internal energy content of the nascent SO(X (3) Sigma(-)) photofragment. These models are unable to fit the experimental observations, if the other fragment is ground-state cyclopropane or propylene, but excellent agreement is obtained for the 1,3-trimethylene diradical, which is believed to be produced in the triplet state.