Based on the clinical practice with families, it was observed that certain secrets assume a fundamental function, entangling the family members in unconscious alliances and denegative pacts. Such a situation favors the emergence, within the family, of primitive angsts and fantasies related to their effects, their maintenance and possible discovery. These questions become particularly pertinent in clinical encounters, not only because of the psychodynamic involved, but also because family secrets resonate in the therapist, as well as in the therapeutic process overall. In regards to the countertransference, the therapist can be faced with diverse sensations, such as headache, numbing, anxiety, and confusion. He might also experience embarrassment when dealing with certain themes, as if he had lost his ability to think and establish connections among mental contents. He might be disturbed by these contents, and sometimes forced to establish agreements with some family members in detriment to other members. In contrast to these experiences, we also observe a detective-like curiosity emerging in the therapist when in contact with these families, which may compromise both the therapeutic relationship and the treatment itself. Given the difficulties involved in these situations, one may ask: how can the therapist understand these counter-transferencial phenomena mobilized in situations that involve family secrets, and how can he use them in the benefit of treatment? Aiming at answering these questions, a literature review on the counter-transference concept was conducted, from the first conceptualizations of this clinical phenomenon established by Freud (1910), Melaine Klein (1946), Paula Heimann (1950; 1969) and Racker (1948) to the notions of family counter-transference (Eiguer, 1995) and mythical counter-transference (Losso, 2001). Later, it was approached the psychoanalytical literature regarding family secrets, differentiating the types of secrets that are fundamental, those that constitute the psyche and the capacity to think autonomously from those that are experienced as angst, shame and/or humiliation. Finally, we attempted to articulate counter-transference and family secrets to the considerations regarding the techniques involved in treating these clinical situations.