SummaryDuring two surveys of beet root crops in South Kazakhstan and Central Asia conducted in 1988 and 1989, 465 of 990 samples were found to contain beet mosaic virus (BMV) by double‐antibody sandwich (DAS) ELISA. BMV infection was widely scattered in the area surveyed, and its incidence varied considerably, reaching 100% in some fields adjacent to beet seed crops. BMV isolates from Kazakhstan, Kirgizia, Uzbekistan and Ukraine were found to be serologically closely related in DAS‐ELISA test. Beet yellows virus (BYV) was not detected in any location surveyed in South Kazakhstan and Central Asia. BYV spread into the area is probably prevented by its geographical isolat