Graft-versus-host disease (GVHD) is the most common life-threatening complication of allogeneic hematopoietic stem cell transplant (HSCT) with the GI tract being a commonly involved site. Current guidelines recommend a platelet count of at least 50x103/μL and absolute neutrophil count (ANC) of 500 cells/μL to mitigate bleeding and infection risk, however this is based on limited data. Given that patients with hematologic malignancies who have undergone HSCT are prone to severe cytopenias, we aim to determine whether severe thrombocytopenia or neutropenia predict poor outcome in this population. We identified 159 endoscopies (upper endoscopy, flexible sigmoidoscopy, colonoscopy) from our institutional database performed on patients who underwent HSCT for hematologic malignancies to evaluate for GVHD. A multiple logistic regression was performed to determine whether pre-procedure platelet count above 50x103/μL, pre-procedure hemoglobin, and pre-procedure ANC predict adverse outcome (bleeding/infection within 1 week or death within 1 month of endoscopy) while controlling for age, sex, pathological diagnosis of GVHD, and days since HCST. 159 endoscopies were performed on patients with mean age 53+16 years, 53.5% women, and median 96 (28-327) days since HCST. The most common diagnoses were AML 55/159 (34.6%), B-ALL 30/159 (18.9%), and CML 14/159 (8.8%). Diarrhea 105/159 (66.0%), nausea/vomiting 63/159 (39.6%), and abdominal pain 31/159 (19.5%) were the most common indications for evaluation of GVHD. Abnormal pathology was most frequently found in the stomach 74/159 (46.5%), duodenum 66/159 (41.5%), and sigmoid colon 54/159 (34.0%). The majority of patients were on tacrolimus 101/159 (63.5%), sirolimus 70/159 (44.0%), and hydrocortisone 59/159 (37.1%) immunosuppression. Bleeding occurred following 5/159 (3.1%) endoscopies, with successful hemostasis in all cases. Death within 1 month of endoscopy occurred in 7/159 (4.4%). A pre-procedure platelet count above 50x103/μL (OR, 0.24; 95% CI, 0.06-0.94; P=0.04) and increased pre-procedure hemoglobin (OR, 0.54; 95% CI, 0.33-0.88; P=0.01) were associated with decreased odds of adverse outcome following endoscopy. Although a platelet cutoff above 50x103/μL was associated with lower odds of adverse events post-endoscopy, the overall risk of endoscopic procedures was low. In our series, under 4% of endoscopic interventions resulted in bleeding, infection, or fever. As expected, patients with higher pre-procedure hemoglobin conferred a decreased risk of adverse events. Pre-procedure ANC was not significantly associated with adverse outcome. Further characterization of safety at different platelet thresholds is necessary to inform the decision to proceed with endoscopy in this at-risk population.