The aim of our study was to evaluate bone metabolism with measurement of bone mineral density (BMD) after management (chemo-, radiotherapy) for childhood acute lymphoblastic leukemia (ALL). Bone mineral density (g/cm2) of lumbar spine was measured by dual energy X-ray absorptiometry (Norland bone densitometer) in 18 children with ALL and a median of 34 months' post-diagnosis with no history of relapse, secondary malignancy, or transplantation. In addition, patients' BMDs were correlated with particular attention to age, sex and time (years) from completion of chemotherapy. The results were compared with healthy age- and sex-matched controls of the same population and expressed as standard deviation scores (SDS). Mean age of children was 9.8 +/- 3.7 years. Of 18 children (10 boys and 8 girls), 13 were grouped as standard and 5 as high-risk, respectively. Based on z-score values, 9 were classified as normal (z-score <1 SD), 7 as osteopenic (z-score 1-2.5 SD) and 2 as osteoporotic (z-score >2.5 SD). Children with ALL had reduced lumbar BMDs (z score -0.99) in comparison to healthy controls (z score -0.14) (p=0.011), which is indicative of relative osteopenia. Moreover, the reduced BMD was associated with patient age (z score -0.14 and -1.52 for ages <10 and >10 years, respectively, p=0.016). Reduced BMD was not correlated with time from completion of chemotherapy (p=0.33), risk group (p=0.9) and sex (p=0.3). We conclude that children's BMDs are reduced after completion of chemotherapy for ALL. The causes are multifactorial and mainly related to antineoplastic treatments, such as corticosteroids and methotrexate, physical inactivity and cranial irradiation. We suggest that further studies are needed to evaluate the long-term effect on BMD in these children and to prevent pathological fractures later in life.