This review compiles information on the taxonomy, identification, geographical distribution, life cycles, host ranges, occurrence, development and growth in both intermediate and final hosts, pathogenicity, and control measures of AnguilUcola crassus and A. globiceps, swimbladder nematodes of farmed and wild populations of two species of eels, Anguilla japonica and A. anguilla, in East Asia. Anguillicola crassus is distributed in Japan, Korea, Taiwan, and China, while A. globiceps is reported only in Japan and China. These nematodes use cyclopoid copepods as intermediate hosts. Known intermediate hosts are Eucyclops serrulatus (Japan) and Therirwcyclops hyalinus (Korea) for A. crassus, and Mesocyclops leuckarti, T. hyalinus, T. taihokuensis, E. serrulatus, Acanthocyclops viridis, and Cyclops slrenuus (China) for A. globiceps. Anguillicola crassus shows a seasonal occurrence in T. hyalinus with high prevalence in summer, Paratenic hosts are yet unknown in East Asia. Anguillicola crassus is relatively common in farmed and wild populations of Anguilla japonica in East Asia, but A. globiceps is usually found in wild populations of A. japonica in Japan and China. In culture ponds, A. crassus is more prevalent and abundant in A. anguilla than in A. japonica. Although A. globiceps induces only the thickening of the host’s swimbladder wall, A. crassus gives severe pathological effects in A. anguilla and heavy infection leads to host mortality. Prevalence of A. crassus in A. japonica cultured in Japan and Korea is relatively low in winter, whereas prevalence of A. globiceps in wild populations of A. japonica from Japan is high in winter.