A B S T R A C T BACKGROUNDAcute leukemia is characterized by the progressive excessive production of leukocytes in the bone marrow as well as the arrival of immature cells into the peripheral blood. The present study aimed to evaluate the oral hygiene status in patients with acute leukemia. METHODSThe present study included 50 ALL patients referred to the affiliated oncology centers of Kerman University of Medical Sciences from April to December 2015 and 52 healthy children. Data collected from the oral examination included the DMFT/dmft and plaque indexes and the presence of mucositis. Information about the diseases, blood test results, the patients' age, and the type of drug was obtained from medical records. Data was analysed through SPSS software, T-test and Mann-Whitney test at a significance level of 0.05. RESULTSGrade 1 and 2 mucositis was observed in 6 (0.12%) and 1 (0.2%) patients respectively. The plaque index was significantly higher in patients than the healthy group (p= 0.033). The average missing teeth was higher in the ALL group, but it was not statistically significant. There were no statistically significant differences between the individuals with mucositis and those without mucositis (p=0.503). There were no statistically significant differences between the patients and healthy group in terms of the mean DMFT/dmft index. CONCLUSIONSThere were no statistically significant differences between the patients and healthy group in DMFT/dmft index. Statistically significant differences were seen between patients and healthy groups in terms of OHI-S index.