A probabilistic list sphere decoding (LSD) is proposed for LDPC-coded MIMO-OFDM systems. By confining the search to channel-adaptively chosen promising candidate groups, our proposed probabilistic LSD evaluates the more promising candidates earlier in the search, while retaining efficient implementation of the depth-first LSD. Simulation results show that, the proposed LSD significantly improves the error performance for constrained throughput, or increases the throughput for a fixed bit error rate. The proposed LSD can be implemented by simply adding special hardware blocks that perform preprocessing and control the tree traversal. The K-best search algorithm enables efficient implementation of the preprocessing.