PURPOSE: There is a paucity of findings concerning the role of diet in childhood leukemogenesis, whereas the results are equivocal and the studies heterogeneous with regard to food items examined. This case-control study investigates the association of childhood leukemia with food groups, macronutrient consumption, total energy intake and adherence to Mediterranean diet among children aged 5-14 years in Greece. METHODS: A total of 139 consecutive, incident leukemia cases out of which 121 were acute lymphoblastic leukemia were derived from the Nationwide Registry for Childhood Hematological Malignancies along with one : one age- and gender-matched hospital controls. Information on socio-demographic, maternal and child variables and dietary habits was obtained through in-person interviews with the guardians/children. Multiple logistic regression was performed with adjustment for birth weight and possible confounding variables. RESULTS: Higher consumption of added lipids was associated with an increased risk of childhood leukemia, whereas consumption of milk and dairy products with reduced risk. From the macronutrient analysis, a borderline trend linking high protein intake with reduced childhood leukemia risk was observed. CONCLUSION: Consumption of milk and dairy products in the first year of life may protect against childhood leukemia possibly through vitamin D actions, while added lipids may increase the risk through various mechanisms. These results offer a holistic evaluation of children's nutrition and suggest that dietary habits in the early years of life may contribute to the prevention of childhood leukemia.