BACKGROUND Therapeutic alliance is a key component of the psychotherapeutic process. This study estimated the impact of the therapeutic alliance as measured by CALPAS-P in an individual brief psychodynamic psychotherapy program. METHODS To study the impact of the therapeutic alliance patients in psychotherapy answered to the CALPAS-P at the first and third session and to the Self-report Questionnaire (SRQ-20), to the Beck Depression Inventory (BDI) and to the Hamilton Anxiety Scale at the beginning and at the end of psychotherapy. RESULTS The study of the impact of the therapeutic alliance in brief psychodynamic psychotherapy showed that higher TUI scores in the first session were significantly associated to the improvement on the BDI. Patients with best scores in the working alliance, measured at the third PWC session had also significant symptomatic changes. CONCLUSIONS The study of the impact of the therapeutic alliance in brief psychotherapy indicated that patients who perceived that their therapists had the best capability to understand and to be involved in their issues had best results in reducing depressive symptoms and patients with higher capability to form the working alliance reached the best psychotherapy outcomes.