Time is one of the most basic social constructions. There are several different "times" (individual, social, cultural). This article deals with the time variable in systemic therapy--a most important variable, but often underestimated by therapists--and seeks to illustrate, with clinical examples, the peculiar interplay of past, present, and future in the therapy session. The co-creation of the past and future in the therapeutic system is also considered, together with the different temporal horizons of the family therapist and the observation team. In our view, time is one of the key issues in successful therapy: consideration of time can open new perspectives in both therapy and research.