BackgroundLeukemia is a cancer of the early-forming cells. Over the past decade, leukemia racial/ethnic disparities have been documented in the United States of America (USA). Although the Puerto Rican population in the USA represents the second-largest Hispanic population in the nation, most of the existing studies do not include Puerto Rico. We compared the incidence and mortality rates for leukemia and its subtypes in Puerto Rico and four racial/ethnic groups in the USA.MethodsWe used data from the Puerto Rico Central Cancer Registry and the Surveillance, Epidemiology, and End Results Program (2015–2019). The racial/ethnic groups studied were non-Hispanic whites (NHW), non-Hispanic blacks (NHB), Hispanics (USH), and Asian/Pacific Islanders (NHAPI) living in the USA and the Puerto Rico population. We calculated the incidence and mortality rates. The relative risk of developing or dying due to leukemia was also calculated.ResultsCompared with Puerto Rico, NHW [standardized incidence rate (SIR) = 1.47; 95%CI = 1.40–1.53; standardized mortality rates (SMR) = 1.55; 95%CI = 1.45–1.65)] and NHB (SIR = 1.09; 95%CI = 1.04–1.15; SMR = 1.27; 95%CI = 1.19–1.35) had higher incidence and mortality rates; but lower than the NHAPI (SIR = 0.78; 95%CI = 0.74–0.82; SMR = 0.83; 95%CI = 0.77–0.89); and similar to USH. However, we found differences among leukemia subtypes. For example, NHAPI and USH had lower risk of developing chronic leukemias than Puerto Rico. We found a lower risk to develop acute lymphocytic leukemia in NHB than in Puerto Rico.ConclusionsOur study provides a better understanding of leukemia’s racial/ethnic disparities and fills a knowledge gap by examining the incidence and mortality rates in Puerto Rico. Future studies are needed to better understand the factors influencing the differences found in the incidence and mortality of leukemia among different racial/ethnic groups.