A delayed cutaneous response to cold, characterized by areas of erythematous, edematous deep swelling at 9 to 18 hr after experimental ice challenge, was recognized in a 10-yr-old boy and several members of his family. Biopsy of the cold-induced lesion showed edema and an infiltrate of mononuclear cells; mast cells were normal, and immunoglobulins, complement factors, and fibrin were not detected by immunofluorescence techniques. Local cold challenge did not release histamine or induce alterations in the complement system or the enzymes, histaminase, and histamine methyl transferase. The delayed cutaneous response to cold could not be passively transferred with serum or tissue extracts to monkey skin. Family studies suggested an autosomal-dominant mode of inheritance.