Objective: The purpose of this randomized control trial study was to understand the effects of happiness training by Fordyce method on life expectancy in patient’s candidates for heart surgery. This study was conducted on 66 patients who were candidates for heart surgery referred to Heshmat Heart Hospital in Rasht. Patients were randomly divided into two groups of intervention (n=34) and control (n=32) via blocked randomized method. The instrument included a standard Miller questionnaire. The intervention method of Fordyce Happiness Model was implemented via face-to-face sessions within 7 days before surgery every day for 20 to 30 minutes. Data analysis was conducted, based on the results obtained before the intervention, there was no significant difference between the two groups in terms of mean life expectancy score (p=0.643). Life expectancy score after the intervention in the case group was significantly higher than the control group (p=0.032). The findings of this study indicate that Fordyce happiness training can effect on life expectancy in patients undergoing heart surgery.