Doublet and quartet states of the HS radical correlating with H(S-2)+S(P-3,D-1,S-1) were investigated by ab initio calculations, at the CASSCF-MRCI/aug-cc-pV5Z level of theory. Molecular parameters and spectroscopic constants obtained for both the ground (X (2)Pi) and the first excited (A (2)Sigma (+)) states represent the best overall theoretical description of this system to date. Transition moments, transition probabilities, and radiative and predissociative lifetimes were also determined for the X (2)Pi -A (2)Sigma (+) system. The values calculated for the radiative lifetimes of the A state show that previous results were too large. Theoretical predissociative lifetimes, although quite sensitive to the region of crossing of the potential energy curves, reproduce the experimental trends.