The article focuses on the subject marital myths as stereotypical beliefs regarding marriage. It aimed at analyzing the most common and the most destructive for a marriage and a family marital myths, as well as at assessing its relation with age and number of children. The study employed an original Marital Beliefs Questionnaire based on the classification of myths by Lazarus (2002). The findings of the study – conducted on a group of 82 adults – show, that the conviction of the righteousness of marital myths is still relatively strong, especially if pertaining to beliefs, such as, “Husbands and wives should be best friends”, “marriage should be a 50-50 partnership”, “opposites attract and complement each other”. The strength of beliefs of the righteousness of selected myths remains in relations to the age of and the number of children had by the subjects. This relationship is particularly vivid in regard to myths “an unhappy marriage is better than a broken home” and “if your spouse wants to leave, hang on and fight”.