This study considered possible immunological alterations that may be associated with keloid tumor formation. Laser immunonephelometry was used to quantitate circulating immune complexes and complement C3 and C4 among keloid formers. IgG complex level was significantly higher, while C3 and C4 were lower, than in the control population. The raised IgG was positively correlated with C4 (r = 0.15). When considered with reports of earlier workers, keloid genesis could result from genetic predisposition, environmental trigger, or localized and systemic immune complex formations. The relationship of these factors to a disequilibrium between fibroblast synthesis of collagen and turnover degradation still remains unclear.