Background：Narrow-band UVB phototherapy using 311±2nm wavelength is in widespread use due to its greater efficacy and, possibly, safety compared with broad-band UVB sources. Objective：We performed emollient narrow-band UVB(NBUVB) phototherapy to evaluate the clinical efficacy and safety in Korean psoriasis patients. Methods：Fifteen psoriasis patients received narrow-band UVB phototherapy. We categorized each patient into clearing, improvement, or failure groups based on the therapeutic efficacy, and measured the PASI score every two weeks. Results： 1. Among patients who received narrow-band UVB phototherapy, clearing was shown in 40.0% and improvement in 27.7%, and failure in 33.3%. 2. The total number, duration, final and cumulative doses to achieve grade IV were 16.3, 39 days, 1,050mJ/cm2 and 12,125mJ/cm2 respectively. 3. There were some side effects of NBUVB phototherapy such as pruritus(53.3%) and mild burning(13.3%). Conclusion：Narrow-band UVB phototherapy is a effective treatment modality which is convenient and less erythemogenic in psoriasis. It will be used more and more and play an important role in the treatment of psoriasis. (Korean J Dermatol 2000;38(3)：358~362)