Psoriasis is a chronic uncurable skin disease and the number of patients are increasing every year. The symptons of this disease can be controlled by the practices of the patient which is related to knowledge and attitudes under the frame of behavioral change. The purpose of this study was to assemble descriptive data regarding psoriasis patients, to evaluate knowledge, attitudes, and practices of psoriasis patients, to compare attitudes towards psoriasis patients who differed in knowledge, and to compare practices of psoriasis patients who differed in knowledge and attitudes. The sample was composed of 211 psoriasis patients registered for treatment in Dermatological clinic at Siriraj Hospitall,Ramathibodi Hospital,Chlalongkorn Hospital and Institute of Dernatology between August to October 1988. Data was collected by means of three written questionnaires : a practice of psoriasis patient scale, and attitudes towards psoriasis scale and a multiple choice of knowledge about psoriasis. The data was analysed by using percentage, arithmatic means, standard deviation, one way analysis of variance and t-test means, standard deviation, one way analysis of variance and t-test The result revealed as follows : 1. Subjects were predominantly male married, 31-45 years old, liveing with family, with elementarry level of edducation, from upcountry and from a low socio-economic group. The typical age of symptom onset was between 16-30 years with the skin change around head or face. At the time of collecting data, the subjects typically had skin lesion over the body, treated with topical medications. The average subject had experienced one to two exacerbations of sympton within 12 months preceding data collection and had been diagnosed for 6-10 years. Most of the subjects had no family member afflicted with psoriasis. Less than half of the subjects had been taught about psoriasis by physicians. 2. Over all, the subjects tended to have a low level of knowledge, incorrect practices and a good attitudes. 3. Comparison attitudes and practices of psoriasis patients who differed in knowledge and attitudes resulted in the following findings.3.1 There was no significant difference in attitudes towards psoriasis in the patients who differed in knowledge.3.2 There was no significant difference inpractices of sporiasis patients who differed in knowledge.3.3 There was a significant difference, (p < .001) in practices of psoriasis patients who differed in atitudes. On the hasis of this study, the recommendations are presented as the following : the effective nealth teaching for psoriasis patients must be developed by nurses. The teaching should emphasize on the practices the characteristic of psoriasis, its treatment and its contorl. The knowledge about psorasis should be promoted to the public by the distribution of leaflet, poster or public relations. And the nealth team must cooperate, coordinate and set the effective referal system for the upcontry patients. The effect of planned instruction towards the practices fo psoriasis patients and a follow up study of the relationship between health practices and the severity of psoriasis should be studied further.