Mastocytosis is a disease characterized by an increase in the number of tissue mast cells and a concomitant increase in mast cell-derived mediators. To demonstrate the spectrum of skin disease in mastocytosis in the pediatric population, five children with mastocytosis and complaints of urticaria (4/5), bullae/vesicles (3/5), abdominal pain (3/5), flushing (2/5), headache (1/5), and bone pain (1/5) are reviewed. Confirmation of the diagnosis of cutaneous mastocytosis was obtained by histologic examination of a biopsy of lesional skin; however, mast cell numbers in lesional skin did not correlate with plasma histamine levels or the extent of cutaneous involvement. Mastocytosis is a diagnosis that must be recognized in the differential diagnosis of pediatric urticarial diseases.