<b>Background</b><br /> Pregnant women’s psychological well-being affects their emotional state, which in turn has a significant impact on fetal development, the course of labor, and the mother’s adaptation in the postpartum period. Social support, especially partner support, is proven to have a protective effect against stress, worries, and concerns that occur in pregnancy. The main objective of this study was to investigate whether support received from the partner mediates the relationship between pregnant women’s prenatal concerns and psychological well-being.<br /> <br /> <b>Participants and procedure</b><br /> The study involved 137 pregnant women aged 18-40 years. Received partner support was measured with a subscale (Actually Received Social Support) of the Polish version of the Berlin Social Support Scales (BSSS). Furthermore, the Concerns of Pregnant Women Scale (POC) and Ryff’s Psychological Well-Being Scales (PWB) were used. The demographic and pregnancy-related variables were controlled.<br /> <br /> <b>Results</b><br /> The obtained results reveal prenatal concerns, received partner support and psychological well-being to be correlated. Partner support was the strongest predictor of psychological well-being in five domains: environmental mastery, purpose in life, personal growth, positive relations with others and self-acceptance. What is more, statistical analyses confirmed the significance of partner support in mediating relationships between prenatal concerns and two dimensions of pregnant women’s well-being: environmental mastery and purpose in life.<br /> <br /> <b>Conclusions</b><br /> Our analyses confirm the results obtained so far in studies on the meaning of social support, particularly that received from a partner, for the health and well-being of pregnant women. We found that received partner support fully mediated the relationship between the concerns of pregnant women and some areas of their psychological well-being. Due to the received partner support, pregnant women’s prenatal concerns cease to affect their beliefs about the meaning of life, feeling of fulfillment of important life tasks, and beliefs about their ability to cope with the world.