Opportunistic intestinal parasitic infections cause significant morbidity and mortality among HIV infected people due to the down regulation of the immune system. In Ethiopia the burden of this infection is high due to poor personal and environmental hygiene. The present study aimed to find the prevalence and associated risk factors of opportunistic intestinal parasitic infections (OIPIs) in HIV/AIDS patients attending antiretroviral therapy in Debre Tabor General Hospital. A hospital-based cross-sectional study was conducted among patients attending Debre Tabor General Hospital Antiretroviral Therapy (ART) Clinic from December 2019 to February 2020. Direct wet mount, formol-ether sedimentation, and modified Ziehl-Neelsen staining techniques were used for parasitological examinations. Data on CD4+T-cell counts were taken from the patients‘ medical records. Socio-demographic characteristics and potential associated risk factors for OIPIs were collected using structured and pretested questionnaires survey. All the data were analyzed using SPSS version 23. Three hundred and eighty-four ART patients participated in the study. The overall prevalence of intestinal parasitic infections was 31.17% while that of OIPIs alone was 17.9%. Among identified intestinal parasites, Cryptosporidium species accounts for the highest frequency (33/384, 8.59%), followed by Cystoisospora belli (26/384, 6.77%), and Entamoeba histolytica/dispar 19/384, 4.9%). Being rural residence (AOR=0.197, 95% CI: 0.053-0.734, P= 0.015, CD4+ T-cell count <200cell/µl (AOR=49.08, 95% CI: 9.440-228.777, P= 0.000), poor adherence of ART (AOR=7.427, 95% CI 2.488-22.172, P=0.00), diarrheal history less than three-month (AOR=7.063, 95% CI: 1.88226.512 P=0.004), regular trimming of the fingernail (AOR=3.665 95% CI: 1.040-12.918 P=0.043), lack of hand washing habit after toilet (AOR=10.409 95% CI: 1.398-77.497 P= 0.022) and drinking water from the unprotected source (AOR=14.721, 95 % CI: 3.349-64.71 P=0.000) were determinant factor for OIPIs. In conclusion, the study indicated that the co-infections rates of OIPs remain a considerable problem that requires improvement in routine screening for OIPI among ART patients, particularly with those with poor or declining CD4+ T cell counts. Keywords: Antiretroviral therapy, HIV/ AIDS patient, Opportunistic intestinal parasite, Ethiopia