摘要:Background and Aims: Prostate cancer screening applied for early diagnosis of prostate cancer. But it is not usually pursued by men. This study was conducted to determine the effect of educational program based on the Theory of Planned Behavior (TPB) on prostate cancer screening. Methods: A randomized clinical trial was carried out on 68 middle-aged men referring to community houses in Iran. Samples were selected consecutively considering the inclusion criteria. Then block randomization was used to assign the participants into two groups. Data collection included demographic characteristics, knowledge and construct of TPB (Attitude towards the behavior, Subjective norms, Perceived behavioral control, behavioral intention) and behavior. The participants in the intervention group attended a theory based program 4 session twice per week. The participants were evaluated before and two month after the intervention. P 0.05 was considered statistically significant. Results: After the 2 months intervention, the pretest-posttest changes in the intervention group compared to the control group were in the Knowledge 9.26 ± 3.5 vs. 0.03 ± 1.68, Attitude 11.46 ± 3.5 vs. -0.16 ± 1.39, Subjective norms 3.16 ± 2.6 vs. 0.29 ± 1.3, Behavioral control 6.76 ± 4 vs. 0.12 ± 1.60 and Behavioral intention 1.4 ± 1.54 vs. 0.00 ± 1.00 ( P 0.05). While none of the subjects in control group performed the prostate screening, 10 people (33.2%) performed it in the intervention group. ( P 0.001). Conclusions: Educational program based on TPB has a positive effect on prostate cancer screening. It is recommended to set up regular training programs based on TPB to encourage middle-aged men for prostate cancer screening.