Twenty eight patients (18 men and 10 women) with delayed pressure induced urticaria were analyzed. The average age was 35.5 years, and the illness lasted 1-20 years, 4.07 years on average. The spontaneous cessation of illness came in 8 patients after approximately 5.75 years. In 23 patients there was also a classical chronic urticaria. C3, C4, alpha 1 antitrypsin, alpha 2 macroglobulin, immunoglobulin IgG, IgA, IgM and IgE were determined for 15 patients and findings were within normal limits apart from the moderate increase of IgE in 2 patients. Fifteen patients were examined for intestinal parasites and in 3 patients they were found. Also, a pathogenetic mechanism of illness was considered: the role of histamine, proteinase inhibitors, mediators of the delayed allergic urticaria.