Literature has shown the importance of therapeutic alliance in the psychotherapeutic process and seeks to understand factors that can interfere in its establishment, such as childhood trauma and parental bonding. As such, this study aims to evaluate therapeutic alliance in psychodynamic psychotherapy from the perspective of adult patients and the correlation between parental bonding and childhood trauma. A cross-sectional and correlational study was carried out with 180 adult patients who started psychodynamic psychotherapy between May 2015 and May 2016 in a mental health clinic whereby Working Alliance Inventory, Parental Bonding Instrument and Childhood Trauma Questionnaire tools were used. The results show that there are correlations between the father’s care and total alliance, as well as the dimensions of goal and bond, but those with mother did not reach statistical significance. The dimensions of emotional abuse and emotional neglect show an inverse correlation with the therapeutic alliance. These results point to the importance of experience of early relationships in establishing therapeutic alliance, relevance of the father figure in this process, and the need for clinicians to be aware of these attachment factors and patient childhood traumas to establish a strong therapeutic relationship.