A taxonomic study was made of 1348 isolates of Fusarium found in 206 soil samples collected in 1946. Approximately 70% of the samples, or 143, were obtained from 127 localities in Manitoba; the remaining 30%, or 63, came from seven other provinces.Of 25,973 colonies of fungi that developed on the 2060 soil-dilution plates involved in this study, Fusarium accounted for approximately 5%. A total of 14 species and varieties of Fusarium, classified in nine sections of the genus, were isolated; they are F. merismoides Cda., F. poae (Pk.) Wr., F. sporotrichioides Sherb., F. avenaceum (Fr.) Sacc., F. semitectum Berk. & Rav., F. acuminatum Ell. & Ev., F. equiseti (Cda.) Sacc., F. culmorum (W. G. Sm.) Sacc., F. sambucinum Fuckel, F. sambucinum var. coeruleum Wr., F. moniliforme Sheld. emend. S. & H., F. oxysporum Schlecht. emend. S. & H., F. oxysporum var. redolens (Wr.) Gordon, F. solani (Mart.) App. & Wr. emend. S. & H. F. oxysporum, F. oxysporum var. redolens, F. equiseti, and F. solani accounted for approximately 90% of the total Fusarium isolates. F. oxysporum was by far the most prevalent species isolated. With the exception of F. merismoides, all of the species isolated were found previously to be seed-borne by cereals and to be associated with common root rot of those crops.