Objectives: Recent studies have shown that tailored messages for cancer screening to the beliefs and stage of cancer screening behavior of individual women increases the take-up probability. Many studies on cancer screening have used the Transtheoretical Model (TTM) to identify variables associated with cancer screening behavior. This study was carried out to identify the cognitive-behavioral factors associated with stomach cancer screening among women aged 40 years and over, and to develop and evaluate a tailored educational program for stomach cancer screening by stages of change. Methods: Building on the TTM constructs, we conducted a quasi-experimental study(N=283) to test the effectiveness of a tailored educational program for endoscopic stomach cancer screening. We carried out pre and post tests in the experimental group(N=162) and the control group(N=121), and the experimental group was subdivided into an on-line group(N=81) and an off-line group(N=81) by educational methodology using e-mail and the postal service. We used the chi-square test, trend test, and paired t-test to test the effectiveness of the program for stomach cancer using a tailored stage-matched messages. Results: To examine the effectiveness of the program for stomach cancer screening by the tailored stage-matched messages, the stage-matched materials were offered to the experimental group(N=162) four times for 4 weeks. The stage-matched materials consisted of the four types for stomach cancer. The tailored message was effective in changing the cognitive-behavioral factors, such as experience process, behavior process, con opinion for stomach cancer, self-efficacy, and the behavioral stages for stomach cancer screening. The stomach cancer screening adherence was higher for the stage-matched materials using postal mail than for those using e-mail. Conclusion: To improve the stomach cancer screening rate, the use of tailored messages for stomach cancer screening will be generated using an expert system. Therefore the implementation of tailored educational program will be supported a partnership between public and private health organizations and increasing awareness of the necessity of community-based interventions.