Introduction: This study examined malnutrition in acute leukemia cases, and its association to the treatment. Methods: 54 cases, consisting of 40 patients with acute myeloblastic leukemia (AML) and 14 patients with acute lymphoblastic leukemia (ALL) were included to the study, where further 34 healthy subjects were also recruited. Body mass index (BMI), triceps skin-fold thickness (TST), mid-arm circumference (MAC) and biochemistry tests were used for the assessment tools of malnutrition. Results: When classified according to BMI, prevalence of malnutrition was 18.5% in all cases, 18% in newly-diagnosed cases, 20% in patients with remission and 16% without remission, and 5.8% in control group. No statistically significant difference was found between groups (p=0.47). Prevalence of malnutrition according to TST and MAC was not difference in patient and control group (p=0.048), (p=0.37). Patients with malnutrition according to BMI had also significant malnutrition according to TST and MAC measurements (p < 0.001). Conclusions: Prevalence of malnutrition was seen at higher percentage in adult acute leukemia cases, which was increased during the course of treatment, and TST measurement was better in establishing malnutrition.