Fusarium spp. are a major components of a root rot disease complex, which threaten pulse crop production systems. Information is limited on the diversity of Fusarium spp. in dry pea growing regions of Montana. The objectives of the study were to identify the Fusarium spp. isolated from dry pea roots and seeds from Montana, and determine their pathogenicity on barley, chickpea, dry peas, lentil, and wheat. Of the 301 Fusarium isolates obtained, 228 and 73 were from roots and seeds. Internal transcribed spacer region of the rDNA and the translation elongation factor genes were used to confirm the identity of the isolates. The Fusarium isolates were 31% Fusarium avenaceum, 19% F. tricinctum, 14% F. acuminatum, 8% F. sporotrichioides, 6.3% F.poae, 6% F. oxysporum, 3% F. culmorum, 2.3% F. redolens, 2% F. graminearum, 2% F. solani, 0.9% F. equisitii, and 0.3% F. torulosum. Pathogenicity of 43 isolates representatives of all the Fusarium spp. were evaluated. Significant pathogenicity was caused by isolates (from roots and seeds) of F. avenaceum on pea, chickpea, lentil, barley, and wheat; F.solani on pea, chickpea, and barley; F. culmorum on barley, lentil, and wheat; F. acuminatum and F. redolens on barley. Due to the cross-pathogenicity of the Fusarium spp. on the pulse and cereal crops, their rotation could propagate the root rot pathogens. Our results suggest the pathogens are seedborne and seed could be a source of inoculum. Effective seed treatments are necessary along with a need for alternative non-host crops for rotation with pulses to break the disease cycle.