Introduction: Pregnancy is one of the most critical periods in women’s lives. Sexual and marital relationships could change due to physical and psychological alterations during this period. Disregarding sexual relationships during pregnancy may result in sexual dysfunction in couples. This study was performed to determine sexual dysfunction and some of its related factors in pregnant women and their spouses.Materials & Methods: In this descriptive-analytical study, sexual dysfunction and some of its related factors, prevalent during pregnancy, were studied in 350 couples, through stratified sampling. A three-part questionnaire was used for data gathering: 1) Demographic, 2) Couples’ attitudes towards sexual activities during pregnancy, and 3) Arizona Sexual Experience Scale (ASEX)_ both female and male versions. The results were statistically sccrutimized.Results: Sexual dysfunction was found in 12.5%, 11.3% and 21% of the couples in the first, second and third trimesters of pregnancy respectively. Altered sex drive in women and sexual dissatisfaction and inability to reach orgasm in men were the most prevalent sexual dysfunctions at each pregnancy trimester. A significant relationship was found between male sexual dysfunction and fear of injury to the fetus (P=0.009) and feeling of guilt (P<0.001) in the third trimester. Similarly, female sexual dysfunction was significantly associated with fear of injury to the fetus (OR=1.5), feeling of decreased sexual attractiveness (OR=1.43), discontent with family’s financial situation (OR=2.67), unwanted pregnancy (OR=4.05) and low level of education (OR=2.49).Conclusion: As couples’ knowledge, beliefs and attitudes regarding sexual activity during pregnancy influence their sexual function, holding educational programs and providing consultation to address the issue during prenatal care are recommended.