The Authors describe the case of a 14-year-old girl who developed a multifocal osteonecrosis (ON), after treatment with chemotherapy and corticosteroids for acute lymphoblastic leukemia (ALL). She came to our attention about 6 months after the beginning of treatment complaining of pain in her left knee and later in both hips and shoulders. Radiography and MRI confirmed the presence of avascular ON at all these sites. The patient underwent bilateral total hip arthroplasty, which was still functioning well at the last follow-up visits at 5 years, and at 5 years and 4 months. ON is increasingly recognized as a complication of the treatment of cancer in children and adolescents, and as patients now frequently survive ALL into adulthood, orthopedists will be increasingly called on to manage this complication affecting multiple joints in children and young adults.