Cross sectional study was carried out on donkeys in some districts of Dhamar governorate with objectives to identify and determine the prevalence of gastrointestinal nematodes of donkeys from December 2017 to May 2018. Fecal samples were collected randomly from 369 donkeys and examined with flotation, McMaster and Baerman fecal examination techniques. The results revealed that, the overall prevalence of gastrointestinal nematodes was 67.75.5%. Seven species of gastrointestinal nematodes were identified. The species identified in descending order of prevalence are: Trichostrongylus axie (35.50%); Oxyuris equi (34.42%); Trichonema or Cyathostomins (24.93), Strongylus vulgaris (21.14%), Strongylus quinus (15.99), Strongylus edentatus (7.046%) and Parascaris equorum (4.065%). Statistically, significant differences (P=0.000) among prevalence of species were observed. The higher prevalence rate recorded in young animals, month of April, male animal and Maghreb anss district was as 83.57%, 78.26%, 68.06% and 88.24% respectively. The age-wise and month variation showed association (P=0.001) with prevalence; while, no with sex and area factors. The higher mean of FEC was recorded in the month of April (1482.04); whereas the lower in the month of December (729.3). It is concluded that working donkeys in study area harbor variety species of gastrointestinal nematodes. Raising awareness regarding gastrointestinal parasites and improved management practices are recommended to control gastrointestinal nematodes of donkeys.