Background and Aim: Sexual satisfaction is a situation in which spouses benefit from a healthy, appropriate and normal sexual relationship. We aimed to investigate the effect of sex education on sexual satisfaction of married women in Bojnourd city. Methods: This pretest-posttest quasi-experimental study was conducted on married women referring to mental health helpers’ center of Bojnourd city in the first half of 2014. Based on sexual satisfaction questionnaire, 30 with the lowest score were divided randomly into two groups of experimental and control. After taking pretest from both groups, the sex education sessions were held in 6 sessions of 2-hours just for experimental group. In addition, two months after finishing the intervention, both groups participated in a follow-up session. The data was analyzed by descriptive statistics methods and univariate analysis covariance (ANCOVA) in SPSS18. Results: Sexual satisfaction in experimental group compared to control group was significantly increased (F = 101.93, p < 0.01) and the effect of education was still stable after two months of follow-up. Conclusion: Sex education, by enhancing the sexual satisfaction, can have an effective role in improving balanced sexual relationships and family health.