Preterm birth is a significant global health issue affecting millions of infants each year, with potential implications for their developmental outcomes. This study investigated the impact of preterm birth on maternal mood states during the early postpartum period and its subsequent effects on mother–infant bonding. Mothers of 90 preterm infants were involved in the assessment of maternal mood states, examined with the Profile of Mood States (POMS) questionnaire and the evaluation of mother–infant bonding, carried out through the Postpartum Bonding Questionnaire (PBQ). Contrary to expectations, there was no significant correlation between preterm birth characteristics and maternal mood states. On the other hand, significant correlations emerged between specific maternal mood states and the quality of mother–child bonding. More specifically, regression analyses showed that feelings of tension, anger, and confusion experienced by the mother tend to negatively affect the quality of her bond with her child. These findings emphasize the crucial role of maternal mental well-being in shaping the mother–infant relationship in the early postpartum period. The study highlights the importance of identifying and addressing maternal mood disorders to promote positive mother–infant bonding and child development, further underlining the need for comprehensive support and interventions for mothers of preterm infants.