Background: Obesity is associated with comorbidities that could cause negative outcome upon delivering intensive care. In pediatric AML patients (pts), obesity was associated with more toxicity and worse prognosis. Here, we study Body-Mass Index (BMI) impact on clinical outcome of adult AML pts. Methods: A total of 180 adult pts with AML between 2003-2011 were enrolled. Retrospective data included demographics, labs, cytogenetics and outcome. LeukemiaNET Standardization (LNS), complete remission (CR), overall survival (OS) and relapse free survival (RFS) were obtained (Dohner E, Blood 2010). BMI of 25-30 was defined as overweight, while >30 as obesity. Fischer’s and Wilcoxon tests were used for comparatives between groups, cox proportional hazards and logistic regression for associations for OS/RFS and CR, Kaplan-Meier test for OS and RFS estimates via JMP software V9.0. IRB approval was obtained according to Helsinki declaration. Results: The median age was 63 years, with 115 (64%) were men. Of 159 pts, karyotype was favorable, Intermediate I, II and adverse in 21 (13%), 76 (48%), 23 (%14) and 39 (25%) pts respectively. Median BMI was 28.2 (range 16.8-47.8). 48 (26%) had normal BMI, 62 (34%) were overweight, and 70 (38%) were obese. At diagnosis, BMI classes were not associated with age, sex, glucose, white blood count (WBC), platelets, blasts, ECOG status, LNS, FLT3/NPM1 status; nor treatment toxicities, CR rates, or relapse after CR. BMI classes were associated with presence of concomitant comorbidities (p=0.047) and glucose levels (p=0.044). In univariate analysis, overweight (OR=1.8, p=0.16) and obesity (OR=1.9, p=0.13) did not affect CR rates. On adjusting for age, sex, LNS, WBC and blast count at diagnosis, only overweight pts had a significant higher CR (76% vs 63%) rates (OR=2.99, p=0.043). OS and RFS were not associated with BMI in univariate (p=0.51) and multivariate (p=0.32) models. Median OS and RFS were not different across BMI subgroups (p=0.52 and 0.59). Conclusions: BMI subgroups showed no correlation with treatment toxicity, LNS, relapse rates, OS or RFS. This should encourage giving therapy to pts regardless of their BMI status. Overweight was associated with better CR rates despite increased concomitant morbidities.