Tritrichomonas foetus causes bovine trichomoniasis in the reproductive tract of cattle and feline trichomoniasis in the large bowel of the domesticated cat. Bovine trichomoniasis is widespread in the USA especially in the Midwest and West and leads to significant economic losses. Although the disease has been endemic for over three decades in Wyoming, one of the largest beef cattle producing states in the USA little is known about its epidemiology and laboratory diagnosis. We statistically analyzed the data collected from the Wyoming State Veterinary Laboratory and the Wyoming Livestock Board. Individual prevalence in beef bull populations in Wyoming between 1997 and 2010 ranged from 0.21% to 2.69%. A steady decline in prevalence was linearly correlated with year since the enforcement of state laws on the disease began in 2000 (R=0.717, P=0.009). One exception was 2009 when a recurrence occurred. Between 2007 and 2010, average herd prevalence was 2.17%, with 15 of the 23 counties having at least one positive herd. In laboratory diagnosis advanced gel-PCR showed 99.9% agreement with traditional cell culture. This is the first epidemiological study on bovine trichomoniasis in Wyoming and demonstrates that T. foetus infection continues to be prevalent in beef cattle in the state where natural service is widely used.