Background: Premarital counseling is a preventive strategy to have a stable marriage. The nurse plays an integral role in premarital counseling including assessing newlywed couples' knowledge & discussing marriage issues, the present aim: to explore the effect of premarital counseling on marital satisfaction of newlywed couples in Port Said governorate. Subjects and method: Design: A quasi-experimental research design was utilized. Setting: The study was carried out in four primary health care centers in Port Said governorate. Subjects: consisted of 100 newlywed couples were equally and randomly assigned to (50 couples in study group and 50 couples in the control group). Tools: The tools used for data collection were; the couple's premarital assessment questionnaire and ENRICH marital satisfaction inventory to assess marital satisfaction at the first & sixth month after marriage. The Results: the current study revealed that the majority (92.0%) of the studied couples at the first month compared to 88.0% at the sixth month were satisfied of their marriage, while more than two third of the control group couples (68.0%) were satisfied at the first month of marriage but at the sixth month, this satisfaction declined to 42.0%. Additionally, there were highly statistically significant differences between the study and control group couples with marital satisfaction at the first & sixth month after marriage p ‹0.01. Conclusion   premarital counseling positively affected newlywed couples' marital satisfaction. Recommendations:    premarital counseling should be considered a priority for newlywed couples to ensure successful and stable marriage.