Afghanistan has one of the highest maternal mortality rates in the world. Inadequate postnatal care (PNC) increases the risk of maternal mortality. This study aimed to analyze the socioeconomic and demographic factors that affect postnatal care utilization. A secondary analysis was conducted in 2019 based on the data from the 2015 Afghanistan Demographic and Health Survey. The sample included 29,461 married women aged 15-49 interviewed during the survey. This was a cross-sectional study in which a frequency distribution of independent variables for the study sample was carried out, Pearson's chi-square test was conducted for association, and the strength of association was measured using binary logistic regression. The study found that 39.9% of married women used postnatal care services. The findings of this study suggest that place of delivery and women who gave birth at health facilities were more likely to use PNC than women who delivered at home. Women age 30-39 and 20-29 positively associated with PNC use compared with mothers aged < 20 years. Each level of women's educational attainment increased their use of PNC, and women with higher education were more likely to use PNC than those without education. Furthermore, women who visited 1-3 and more than four ANC visits were more likely to use PNC than women who did not visited ANC. Moreover, women exposed to mass media were more likely to use PNC than those who were not exposed to mass media. Finally, women who lived in the northern and western regions were more likely to use PNC than those who lived in the central region, while women who lived in the southern and southeastern regions were less likely to use PNC than those who lived in the central region. Therefore, strengthening the provision of information, education, and communication could be a communication channel to further improve PNC utilization. Meanwhile further studies are needed to focus on the quality of maternal health care and PNC services in Afghanistan in order to obtain more precise information.