PURPOSE OF REVIEW: The Food and Drug Administration report of an increased rate of malignancy among children treated with tumor necrosis factor inhibitors is worrisome. These concerns prompted rigorous studies of the incidence of malignancy associated with juvenile idiopathic arthritis, both with and without treatment with specific therapeutic agents. This article reviews studies of the risk of malignancy associated with biologic agents for the treatment of juvenile idiopathic arthritis and childhood-onset systemic lupus erythematosus. RECENT FINDINGS: Several studies demonstrated an increased background rate of malignancy associated with juvenile idiopathic arthritis, although the impact of medication use on the risk of malignancy was less clear. Similarly, childhood-onset systemic lupus erythematosus is likely associated with an increased malignancy risk, and the impact of biologic agents is unknown. SUMMARY: The diagnoses of juvenile idiopathic arthritis and childhood-onset systemic lupus erythematosus are likely associated with an increased background risk of malignancy, irrespective of medication use. Further studies to estimate the risks of malignancy associated with pediatric rheumatic diseases and their treatments are needed. © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins.