Summary: This paper reviews Dynamic Channel Allocation (DCA) in TDMA cellular systems. The emphasis is on distributed DCA, which features decentralized control and adaptability to interference. Performance measures are discussed not only from a theoretical viewpoint but also from a practical viewpoint. Major techniques to enhance the capacity of cellular systems are channel segregation, reuse-partitioning, and transmitter power control. In addition to the performance of conventional cellular systems, differing performance in microcellular systems and multi-layer cellular systems is also discussed.