Abstract Mycotoxins are secondary fungal metabolites that contaminate a variety of feedstuffs and are detrimental to animal health and productivity. The risk of broad-spectrum mycotoxin exposure is elevated for ruminants due to the complexity of their diets. This study investigated the occurrence and contamination levels of mycotoxins in forage-based feeds including corn silage, haylage (including various cuttings of multiple forage sources), and straw samples from across the US and Canada. Samples were screened for the six major mycotoxin groups: aflatoxins, type A trichothecenes, type B trichothecenes (B-Trich), fumonisins (FUM), zearalenone (ZEN), and ochratoxin A via LC-MS/MS technique. Samples submitted for clinical health or performance concerns were excluded from the data set. The B-Trich occurred most frequently (95% positive) among 92 corn silage samples harvested in 2019 followed by ZEN (34%) and FUM (9%). Mean contamination levels (parts per billion, ppb) on dry matter basis were 2,788 ppb, 456 ppb, and 194 ppb, respectively. Only 4% of silage samples were below the limit of detection (LOD) for all mycotoxins evaluated. Among 20 haylage samples from 2019 crop year, B-Trich were the most frequently detected, with 50% of samples positive at a mean concentration of 3,222 ppb. Twenty-one 2019 straw samples were submitted for analysis, with 100% testing positive for some level of B-Trich (mean 2,001 ppb) and 81% ZEN positive with an average of 640 ppb. Seventy-one percent of straw samples were positive for both B-Trich and ZEN. Preliminary mycotoxin survey results from US and Canada suggest B-Trich and ZEN are the most frequently occurring major mycotoxins in 2019 forage-based feed samples. Based on the frequency and levels of mycotoxin contamination identified in the current data set, continued analysis of forage-based feeds is warranted as mycotoxins pose a potential risk to the health, performance, and reproductive success of ruminants.