The aim of this study was to investigate immunohistochemically the influence of cigarette smoking on the socket healing after tooth extraction in rats. Eighty-four male rats were divided into 3 groups; 2 groups were considered as experimental and the other as control. The animals in test 1 were exposed to smoking regimen before the surgery and after the surgery, but the animals in test 2 were exposed to the smoking regimen only before surgery. All animals' maxillary right central incisors were extracted and killed at the 3rd, 7th, 15th, and 28th day. The samples taken on third day after tooth extraction were stained immunohistochemically with fibronectin antibody and the other with type I collagen antibody. On the third day after tooth extraction, samples in the control group were intense stained (3) (+++); in the test 1 they were slight positive (1) (+) and in the test 2 they were moderate positive (2) (+ +). As a result of scoring type I collagen antibody, there was no statistically significant difference between the groups at seventh day, but there were statistically significant differences between the groups at the 15th and 28th day (P = 0.000 and P = 0.001, respectively). Comparison of the paired intense scores of type I collagen antibody staining according to days within each groups were not statistically significant. As a result, we have found out that the healing process of the tooth extraction socket is negatively affected by cigarette smoke.