We examined whether trichomoniasis had been a factor in a dramatic mourning dove (Zenaida macroura) population decline in Fillmore, Utah (USA). We reasoned that if we could not find a high proportion of doves showing clinical signs of disease then the population was not being affected. Prevalences of Trichomonas gallinae in doves were 21% for 1992 and 14% for 1993. We also examined 230 birds and found only one with oral lesions. These prevalences were similar to those observed at the same study site in the 1950's, or reported elsewhere. Based on our results, we believe that trichomoniasis was not affecting the Fillmore mourning dove population at the time of our study.