Internal parasites directly affect the health and production of working equines, which contributes to the reduction in their work output and ultimately in the income of the owner and the community. A cross-sectional study was conducted from November 2016 to April 2017 in and around Guder town, west Shewa, central Ethiopia to estimate the prevalence of equine internal parasites and assess the potential associated risk factors. A total of 384 faecal samples from equine species (152 donkeys, 107 horses, 125 mules) were collected and examined for the presence of eggs of parasites using standard coprological methods. Out of these, 341(88.8%) equines were found positive for one or more internal parasites. The prevalence of internal parasites in donkeys, horses, and mules was 95.4%, 89.7%, and 80% respectively.Out of 341 positive samples, the species of parasites found were Strongylus spp. (40.8%), Parascaris equorum, (25.5%), Oxyuris equi, (17.6%), Strongyloides species(8.8%), Fasciola (10.6%), Dictyocoulus arnifieldi,(10%) and Anoplocephala species (1.5%). Single (86.2%) and mixed (13.8%) parasite species. There was significant difference (p<0.05) in the prevalence between species (χ 2 = 16.47, p=0.001) and the purpose of keeping equines (χ 2 =12.41, p=0.006) in which more number of donkeys and pack animals were positive for parasites than other animals. However, there was no statistically significant difference among, age, sex, house, feed, and body conditions of study animals. In conclusion, this study revealed that the occurrence of internal parasites in equine species in the study area was common phenomenon, especially in donkeys. Hence,strategic prevention and control of internal parasites should be implemented.