Background：In the patients complaining of alopecia or hair thinning, many different disease entities are included. Although there have been many clinical studies on each individual disease of them, few reports dealing with all of the alopecia patients in a dermatologic clinic are found. Objective：We attempted to reveal the collective clinical aspects of all of different diseases resulting in loss of hairs in a dermatologic clinic. Method：Clinical records of 1505 patients with various alopecia seen from March 1978 to July 1998 at the department of Dermatology, Chonbuk National University Medical School were analyzed for their diagnosis, age, sex, and annual distribution in all dermatoses. Among them, 1252 cases were further studied for their subtypes, causes, result of treatments and other details. Results：1. The incidence of total alopecia patients among the total new patients during the period was 2.9%(1505/51140), 1.24% in average during the 1980s and 4.7% during the 1990s. 2. The incidence of different alopecia was as follows: alopecia areata; 55.0%(827/1505), androgenetic alopecia; 26.1%(392/1505), telogen effluvium; 7.0%(106/1505), trichotillomania; 3.6%(54/1505), accidental alopecia; 1.9%(28/1505), seborrheic alopecia; 1.2%(18/1505), and nutritional alopecia: 0.9%(14/1505). 3. The sex distribution showed 761 men and 744 women. The age distribution showed a peak incidence in the third decade(37.4%, 563/1252). 4. The duration from the recognition of initial hair loss to the time of the first visit to the hospital was less than 3 months in 46.4%(581/1252), and less than 6 months in 60%. 5. The subtypes of 686 cases of alopecia areata consist of 549(80%) cases of common type, 77(11.3%) cases of alopecia totalis, and 60(8.7%) cases of alopecia universalis. 6. The relapse rate after treatment in alopecia areata was 29.4%. In 7.4% there was no response to the treatment. 7. Of the 160 male androgenetic alopecia patients Hamilton's type II and III were most common (92.5%). Of the 60 female androgenetic alopecia patients Ludwig's type I was most common(58.5%) 8. The presumed causes of telogen effluvium was as follow: delivery(23.1%), febrile illness (22.0%), traction(8.8%), drug administration(6.6%), crash diet(5.5%). 9. In trichotillomania, the male to female ratio was similar. 70% of the patients belonged to the 1-20 year age group. (Korean J Dermatol 2000;38(10)：1348~1357)10. Accidental alopecia or the alopecia caused by accidental trauma occurred most commonly in women(79%, 22/28). 11. All patients of nutritional alopecia or the alopecia due to diminished diameter of the hair(14cases) and traction alopecia(6cases) were women. Conclusion : We made clinical analysis of all of the patients complaining of hair loss by any causes during the past 20 years from March 1978 to July 1998.