Background: Unlike with solid organ cancers, little data is available on how diabetes mellitus (DM) and hematologic malignancies interact to affect survival and glycemic control. We examined the impact of DM on survival in patients with leukemia and the effect of leukemia on glycemic control. Materials and Methods: Patients with leukemia with and without DM were matched 1:1 (2007–2017), 70 matched pairs (total N=140 pts) were included in the analysis. We compared characteristics between cases and controls and assessed survival with the Kaplan-Meier method and Cox proportional hazards model. Mixed models compared hemoglobin A1c (HbA1c) and glucose levels over time. Results: The median age of patients at diagnosis was 56 (18–94); 60% were male and 89% had acute leukemia. Among those with DM, HbA1c was only recorded in 25 of 70 patients during the year following cancer diagnosis and was 6.8%. There was no change in HbA1c values over time in these DM patients. Mean glucose was significantly different between DM and non-DM patients (p<0.001). Time (days since leukemia diagnosis) was significant (p<0.001) and there was a significant interaction effect (p=0.01). Glucose values increased in the DM patients during the year following diagnosis, while remaining stable in those without DM. Median follow-up time was 23.2 months. Three-year survival was estimated at 46% for DM patients versus 45% in non-DM pts by Kaplan Meier method (p=0.79). Hazard ratio (stratification for matched pairs) was 1.05 (95% CI: 0.57 - 1.94; p=0.88). Three-year relapse-free survival was estimated at 34% for DM patients versus 43% for non-DM patients (p=0.58). Hazard ratio (stratification for matched pairs) = 1.10 (95% CI: 0.61–1.98; p=0.76). Conclusions: DM did not adversely impact survival in patients with leukemia. Leukemia and its treatment did not affect glycemic control. This should be reassuring to hematologists and endocrinologists who treat patients with leukemia and diabetes.