PURPOSE: p21/WAF1/CIP1, p27/KIP1 and p57/KIP2 are negative regulators of the cell division cycle. We evaluated the expressions of KIP CDK inhibitors and examined the relationship of clinicopathologic parameters and cell proliferation index in gastric adendegrees Carcinomas. MATERIALS AND METHODS: The study was carried by the TUNEL method for apoptosis, immuno histdegrees Chemical staining for PCNA, p53, p21/WAF1/CIP1, p27/KIP1, and p57/KIP2 proteins and Western blot for KIPs proteins of normal and cancer tissues of stomach. RESULTS: In normal gastric mucosa, p21/WAF1/CIP1 and p27/KIP1 proteins were expressed both mainly to the superficial portion of the glands with intestinal metaplasia and stromal cells. p57/KIP2 protein was also expressed normal crypt glandular epithelial and stromal cells. In gastric adendegrees Carcinoma, p21/WAF1/CIP1 was positive in 25 of 70 (35%) and showed significant decrease in deep tumor invasion (p=0.015) and the presence of angioinvasion (p=0.013). There was signi ficant inverse correlation between p27/KIP1 expression and cell proliferating index. p21/WAF1/ CIP1 expression was related to lower apoptotic index. Western blot analysis of KIP CDK inhibitors showed marked down-regulation of p21/WAF1/CIP1 protein in cancer than normal tissue, but alternative expression in p27/KIP1 and p57/KIP2 proteins. CONCLUSION: The above results indicated that the expression loss of KIP CDK inhibitors was contributed to tumor progression and aggressiveness in gastric adendegrees Carcinoma.