The effects of soil treatment with Benomyl or Captan on the rhizosphere fungi of Allium cepa were investigated. The mycoflora of the rhizosphere was considerably inhibited by both fungicides. Captan was more inhibiting than Benomyl, but the latter seemed to be more persistent. The fungi isolated from the rhizosphere of control plants, plants treated with Benomyl or with Captan are listed and differences between treatments are discussed. The total number of species isolated from the rhizosphere of control plants was 65, Benomyl 44 and Captan 29. The growth of onions receiving fungicide treatment was greatly reduced: differences in dry weight were 31% (Captan) and 36% (Benomyl) less than control plants.