To study the expression of the Kruppel-like transcription factor 6 (KLF6) in human gastric carcinoma and normal gastric mucosa tissues, and to explore the role of KLF6 in the carcinogenesis and tumor progression and its clinical significance. Expression of KLF6, P21(WAF1) and PCNA was investigated by immunohistochemistry for 69 surgically resected gastric carcinoma tissues and corresponding normal gastric mucosa tissues, respectively. The correlations of KLF6 expression with clinicopathological characteristics, P21(WAF1) and PCNA were examined. Positive-expression of KLF6 was 64 out of 69 cases (92.8%) in normal gastric mucosa and only 23 cases (33.3%) in gastric carcinoma. Expression of KLF6 in the gastric carcinoma was remarkably lower than normal gastric mucosa. Decreased expression of KLF6 in gastric carcinoma was significantly associated with histological differentiation (P < 0.01), TNM stage (P < 0.05), lymph node metastasis (P < 0.01) and distant metastasis (P < 0.05). There was no significant correlation between KLF6 expression and sex, age. Meanwhile, expression of KLF6 was associated with expression of P21(WAF1) in both normal gastric mucosa and gastric carcinoma (P < 0.05). In addition, decreased expression of KLF6 in gastric carcinoma was positively associated with PCNA level (r = 0.719, P < 0.01) by association analysis. Down-regulation of KLF6 might play an important role in the carcinogenesis and development of human gastric carcinoma and have significant clinical value.