Psoriasis is generally accepted as an autosomal, irregular, dominantly inherited dermatosis. The incidence of hereditary psoriasis may be as high as 80%. Recently five related persons with psoriasis have come under our care. Careful questioning enabled us to obtain information about their ancestors going back five or six generations. The following genetic charts will be of interest to all who manage this stubborn dermatosis. All five patients are identified by an asterisk on Charts 2 and 3. The cases reported as psoriatic were those who were diagnosed as such by physicians or those who had lesions resembling psoriasis, as described to us. Naturally, many of those identified as "normal" may have, have had, or will yet develop psoriasis. Comment on Charts A psoriatic woman (A) married to a normal man