The two-volume set CCIS 2061 and 2062 constitutes the refereed post-conference proceedings of the 18th International Conference on Bio-Inspired Computing: Theories and Applications, BIC-TA 2023, held in Changsha, China, during December 15-17, 2023. The 64 revised full papers presented in these proceedings were carefully reviewed and selected from 168 submissions. The papers are organized in the following topical sections: Volume I: Evolutionary Computation and Swarm Intelligence; and Membrane Computing and DNA Computing Volume II: Machine Learning and Applications; and Intelligent Control and Application.