Background: If not diagnosed earlier, chromoblastomycosis has a chronic evolutional course that may cause several problems, such as difficulty in managing therapy because of the recrudescent character of the disease, potential association with the growth of epidermoid carcinoma in affected regions, and poor quality of life and work incapacity to the patient. Although infrequent, new cases are reported in the state of Rio Grande do Sul every year, ratifying the necessity for further studies on this disease. Objective: The purpose of this study was to review clinical features and response to therapy in patients with chromoblastomycosis and present data on the demography and history of this disease in the state of Rio Grande do Sul, Brazil. Methods: We reviewed case records of 100 patients with skin lesions caused by chromoblastomycosis, who were treated between 1963 and 1998. The cases were confirmed by the histopathologic and mycologic analyses made by the Dermatology Service of the Universidade Federal do Rio Grande do Sul at the Santa Casa de Misericórdia Hospital. Results: There was a predominance of male patients (4:1) and of white farmers whose ages ranged from 50 to 59 years, with lesions on their lower limbs. Most of them were from the northern regions of the state. The average time between the appearance of the disease and medical diagnosis was 14 years. The verrucous type proved to be the most frequently reported lesion (53%). Thorn wounds were associated with the disease in 16% of the cases. Lesions uncommon to some parts of the body were also reported. In two of the cases, cutaneous lesions caused by paracoccidioidomycosis and chromoblastomycosis were found in the same patient. Epidermoid carcinoma was found in the same parts of the body affected by chromoblastomycosis. Eumycotic mycetoma and chromoblastomycosis were associated. Fonsecaea pedrosoi was found in 96% of the cases, and Phialophora verrucosa in 4% of the cases. Conclusion: In our study, we observed a predominance of cases in the regions of Missões and Alto Uruguay, followed by the upper and lower northeastern slopes and the lowlands. Severe cases of chromoblastomycosis with intense skin involvement (eg, lesions with carcinoma) were observed. Statistical analysis showed recrudescence of the disease in 43% of cases despite the treatment used. (J Am Acad Dermatol 2001;44:585-92.)