Objectives: Acute graft versus host disease (aGVHD) is a common complication of allogeneic hematopoietic cell transplant (HCT) and is associated with morbidity and mortality. Identifying those at risk for developing aGVHD is crucial for early intervention. The current study assessed whether scores on a brief cognitive screening measure could identify those that develop aGVHD by 100 days post-HCT.Methods: Participants were 37 patients undergoing allogeneic HCT, assessed prior to transplant, and at 30- and 100-days post-HCT. Of those completing all evaluations, patients were divided into those who did (n = 14) and did not (n = 16) develop aGVHD by day 100 post-HCT. At 100 days post-transplant, groups did not differ on relevant demographic factors, disease, conditioning regimen, relatedness of donor, stem cell source, steroid use, total body irradiation use, human leukocyte antigens (HLA) match, or frequency of infection.Results: At 100 days post-HCT, those with aGVHD performed significantly worse on a working memory measure than those without aGvHD. The presence of aGVHD at day 100 increased significantly with every one standard deviation decrease in working memory from baseline to 30 days post-HCT (odds ratio = 3.08; 95% CI: 1.00-9.36). These findings were observed despite a small sample size and statistically controlling for multiple analyses.Conclusions: While this study is exploratory in nature, and has a small sample size, findings suggest that early detection of working memory declines could coincide with, or signal the development of, aGVHD. Potential etiologies are discussed. Implementing early cognitive screening within the first 30 days post-HCT may be useful in identifying patients at risk for aGVHD.