It is unknown whether the high rates of cure reported for Burkitt lymphoma/leukemia (BL) patients treated with chemoimmunotherapy can be verified outside published series and clinical trials. We used the Surveillance Epidemiology and End Results (SEER) database to describe time trends in outcomes of BL in the United States. Cases were divided into 2 eras based on year of diagnosis, reflecting improvements in HIV management, BL treatment, and supportive care. There was a marked improvement in survival among BL cases diagnosed in the 2002-2008 era (n = 1922) relative to 1973-2001 (n = 1769) with 5-year relative survival estimates of 56% and 43%, respectively (P < .001). Five-year relative survival improved from 71% to 87% for ages 0 to 19 (n = 970), 35% to 60% for ages 20 to 39 (n = 897), 28% to 48% for ages 40 to 59 (n = 1047), and from 25% to 33% for ages ≥60 (n = 777). In multivariable analysis, the 2002-2008 era (HR = 0.76, P < .001) was associated with lower mortality. Conversely, older age, black race, and advanced stage were associated with higher mortality. More effective therapies are needed for older patients with BL, along with improved access to modern therapy for younger patients.