Thrombotic events that occur in children are relatively rare and are mostly associated with indwelling catheters, infectious processes, surgical procedures, or genetic defects or deficiencies. However, case reports, case series, and registries continue to report children who exhibit the clinical features often associated with the antiphospholipid syndrome. Many of these cases are well-documented and also meet the published research criteria for the antiphospholipid syndrome. Children with antiphospholipid antibodies generally do not experience a high rate of thrombotic events. This is in part related to developmental differences in levels of coagulation proteins and to the relative health of the vascular endothelium compared with that of adults. Therapeutic issues in children may be oriented more toward identifying risk factors and providing preventive health, as well as more short-term treatment of transient events.