OBJECTIVE To explore the expression of Snail and Slug in primary cervical squamous cell carcinoma (CSCC) and their relationship with KAI1 expression. METHODS The expressions of Snail, Slug, and KAI1 proteins were examined by immunohistochemistry in 154 specimens of CSCC tissues, 50 specimens of cervical intraepithelial neoplasm (CIN), and 40 specimens of normal cervical tissues. RESULTS The positivity rates of Snail, Slug, and KAI1 expression were 0%, 2.5%, and 95.0% in normal cervical tissues, 32.0%, 34.0% and 64.0% in CIN tissues, and 66.2%, 66.9%, and 43.5% in CSCC tissues, respectively, showing significant differences in the rates among the 3 groups (P<0.05). The expressions of Snail, Slug, and KAI1 were significantly correlated with the histological grades of the tumor, depth of invasion, lymph node metastasis, International Federation of Gynecology and Obstetrics (FIGO) stages, and postoperative survival time (P<0.05). The expressions of Snail and Slug were positively correlated (r=0.752, P<0.001), and both of them were negatively correlated with the expression of KAI1 (P<0.001). Kaplan-Meier analysis showed that patients positive for Snail and Slug had significantly lower survival rates than the negative patients (P<0.001), while a positive expression of KAI1 was associated with a higher survival rate of the patients. Cox regression analysis identified Snail, KAI1, and FIGO stage as independent factors that affected the outcomes of CSCC (P<0.05). CONCLUSIONS The expressions of Snail, Slug, and KAI1 are related to the tumor grade, FIGO stage, invasive depth, lymph node metastasis, and prognosis of CSCC, and their combined detection can help estimate the outcomes of the patients.