Starting from concepts originated from the psychoanalytic theory, the objective is to identify, to describe, to discuss and to analyze expressions of unconscious oedipal and sexual fantasies that took place in a play therapy group of preadolescents. This out-patient group worked according to the psychodynamic reference for two years, it was open and constituted by male and female children, with ages of ten and eleven years old. The clinical-qualitative method was utilized in the research. Sexual fantasies were present in a significant number of sessions. On the other hand, oedipal fantasies were less frequent and less evident, since they usually were repressed or unclear, almost always in the transference of therapists and of the children. Unconscious fantasy expressions of union with the progenitor of the opposite sex were observed, as well as competition among siblings and anxiety of castration.