Three-dimensional potential energy functions have been generated ab initio for the X(2)Pi electronic ground state of CCS- and used in variational Renner-Teller calculations including electron spin. Rovibronic levels (J = P) for J less than or equal to 5/2 are given for energies up to 4000 cm(-1). The pattern of the levels is compared with that of CCO-. In the case of CCS- the quartic force fields, equilibrium geometry, electric dipole moment, the electronic affinity and the Franck-Condon factors for the X (2)Pi (CCS-) --> X(3)Sigma(-) (CCS) photodetachment spectrum are calculated.