Purpose: 1-Describe Localized gastrointestinal histoplasmosis as an unusual cause of lower GI bleeding in patients with HIV. Methods: A 27 year old male from Guatemala with no PMH admitted with one-month history of hematochezia associated with LLQ abdominal pain, generalized weakness, intolerance to exercise and dizziness. No fever, chills, melena, and change in his weight. PE: BP108/61, HR100 bpm, T°97.5°, RR 18. HEENT: Pale mucosal membranes, no ulcers, no thrush, Neck supple, no lymphadenopathy, Lungs clear, CVRR, Abdomen soft, NT, no organomegaly. LABS: BUN 17 mg/dl, creat 0.9 mg/dl, Na131, K 3.7, Cl 102, Ca 7.7, TP 7.3, ALB 2.3 gr/dl, AST 34 IU/lt, ALT 20 IU/lt, LDH 159 IU/Lt, Bil: 0.3 mg/dl, AP: 80 IU/dl, Hb 8.8, Ht 26.6%, WBC 4500/mm3, N: 64%, L: 27%, PLT 336,000/mm3, CT scan of the abdomen: diffuse periaortic and mesenteric lymph nodes, no hepato-splenic abnormalities, COLONOSCOPY: 2 colonic ulcers at 40 and 50 cms, multiple superficial ulcers, no hemorrhoids, BIOPSY: lymphoid aggregates and yeast morphologically compatible with histoplasma species. positive Elisa for HIV, negative urinary histoplasma Ag, Normal immunoglobulin level, CD4:104. Bone marrow biopsy normal and CT of the chest unremarkable. Patient was started on Amphotericin B with excellent clinical course no further bleeding episodes. Results: Although gastrointestinal histoplasmosis is considered uncommon, Autopsy studies reveal GI involvement in 70–90% of patients with progressive disseminated histoplasmosis (PDH). Clinical manifestations range from diarrhea, dysphasia, intestinal perforation or obstruction. Gastrointestinal histoplasmosis is an unusual cause of lower gastrointestinal bleeding (LGIB) in AIDS population with only few cases reported. Most common causes of LGIB in AIDS population are CMV colitis, Idiopathic colonic ulcers, hemorrhoids, anal fissure and Kaposi's sarcoma. Our patient had no systemic symptoms at the time of presentation, and had negative urinary histoplasma antigen (which is positive only in 25% cases of localized forms). Although in 23% patients the colonic mucosa is grossly normal (specially inmunocompromised patients), colonic ulcers 0.2–4 cms diameter, with raised borders surrounded by erythema may be found with microscopy revealing lymphohystiocytic infiltrates, histiocytes and fungi inside macrophages, Treatment is with amphotericin B followed by itraconazole. Conclusion: This case depicts gastrointestinal histoplasmosis as an unusual cause of LGIB in AIDS patients.