IntroductionContact with second-hand cigarette smoke includes inhalation of cigarette smoke caused by the burning of the cigarette itself and inhalation of smoke exhaled by the smoker. Wife's pregnancy can be a motivating factor to change the behavior of men who smoke. Therefore, this study was conducted with the aim of designing, implementing and evaluating an educational program regarding the effects of second-hand smoke in pregnancy on the knowledge, attitude and performance of male smokers.MethodologyThe present study is an interventional type of pre-test and post-test. In this phase, sampling from health centers in Isfahan was done randomly between March and July 2019, the participants were 140 smoking spouses of pregnant women, who visited health centers to receive pregnancy care, and were divided into two intervention groups and control were divided. The data collection tool was a researcher-made questionnaire on men's awareness, attitude and performance regarding second-hand smoke. All data were analyzed with SPSS18 software and Chi-score, Fisher, t-test.ResultsThe average age of the participants was 34 years. There was no significant difference between the comparison of demographic variables in the intervention and control groups (p > 0.05). The results of the paired t-test for comparing before and after the training showed that the average score of the emotional dimension of attitude in the two groups of intervention (p < 0.001) and control (p < 0.001), awareness (p < 0.001) and behavior (p < 0.001) was significantly increased in the intervention group after the training, and according to the independent t-test, the average score of the items mentioned after the training in the intervention group was higher than the control group (p < 0.05). Regarding perceived sensitivity (p = 0.066) and perceived severity (p = 0.065), no significant difference was observed.ConclusionThe awareness, emotional aspect of men's attitude and behavior regarding secondhand smoke increased, but the perceived sensitivity and severity in this regard was not significant despite the increase, so the current training package is effective in training, but considering more training sessions It is necessary with more concrete training with model or training videos in order to improve the sensitivity and perceived intensity of men.Trial registration: Registration of this randomized control trial has been completed with the Iranian Registry of Clinical Trials, IRCT20180722040555N1.