Aim: This study aimed to determine the relationship between birth memory and trauma and maternal functioning in the postpartum period. Methods: This cross-sectional study included 584 mothers in the postpartum period between 1 January 2022 and 1 April 2022. Data were collected using a personal information form, the Barkin Index of Maternal Functioning (BIMF), the Birth Memories and Recall Questionnaire (BirthMARQ) and the City Birth Trauma Scale (CityBiTS). Results: The participants’ mean scores for the overall BIMF, BirthMARQ and CityBiTS were 81.41 ± 9.28, 80.30 ± 21.21 and 15.85 ± 11.30, respectively. Their sociodemographic characteristics did not affect their maternal functioning; however, maternal functioning improved with the number of pregnancies. While emotional memory (BirthMARQ subscale) negatively affected maternal functioning (p < 0.001), the centrality of memory (BirthMARQ subscale) positively affected maternal functioning (p < 0.001). The hyperarousal (CityBiTS subscale) score significantly and negatively affected the total maternal functioning score, explaining 6 % of its variance (F = 9.176, p = 0.001). Conclusion: This study demonstrated that birth memory and trauma affected maternal functioning. The mother's functional status in the postpartum period reflects the physical and psychosocial changes associated with pregnancy and birth. Therefore, for women to have positive birth memories and emotions when recalling the birth, their emotional health and physical care should be supported during labour and the postpartum period.