The objective of this study was to review the epidemiologic literature on exposure to diesel exhaust (DE) exposure and leukemia risk. No cohort studies, nine case–control studies, and nine studies based on routine statistics and record linkages provided results useful to assess the risk of leukemia, and in particular acute myeloid leukemia (AML), among exposed workers. No formal pooling of the results was possible. The available studies do not consistently suggest an increased risk of leukemia, and specifically AML, among workers exposed to DE. For none of the occupational groups potentially exposed to DE, the results suggest an association, and sporadic positive results are counterbalanced by negative associations and might result from reporting bias. DE exposure does not appear to be associated with increased risk of leukemia.