Twenty-four (1.6%) of 1466 children with acute lymphoblastic leukemia (ALL) treated at St. Jude Children's Research Hospital had vertebral compression fractures at diagnosis. When compared with patients without this complication, they were more likely to have good prognostic features, including a leukocyte count of greater than 25 X 10(9)/l, a leukemic cell DNA index of greater than 1.15, and hyperdiploidy (greater than 50 chromosomes). Complete remission of ALL was induced in all patients, and symptoms of vertebral compression fractures abated following antileukemia therapy. Although the diagnosis of ALL was delayed for some patients because this unusual presenting complication was not recognized as such, their treatment outcome was as good as that for other children with "standard-risk" ALL.