The purpose of this study was to estimate and achieve the factors that have an influence on the evolution of the Chron's disease. This study was done in 124 patients reaching the diagnosis of Chron's disease between 1988 and 1997. The evolution of this disease was achieved in 87 patients. The Chron's disease was inactive among 31 patients (35-6%)--with discontinous evolution in 42 patients (48.3%) and active chronic in 14 patients (16-1%). The active chronic form of Chron's disease was twice more frequent among the smokers and the patients with age above 40 years--but this difference has no statistical significance. The indication of surgical treatment was realised in 21 patients and it takes place as result of failure of medical treatment in 16 patients (76-2%)--an abcess in 2 patents (9-5%) and iatrogenic perforation in 1 patient (4-8%). The age-sexe-smoke--the intensity of the initial attack and the nature of the treatment had no influence in the need of the surgical interfference. The Chron's disease showed the less severe evolution in this study--the age above 40 years and the consumption of smoke increased the frequency of active chronic form.