The paper puts forward the idea that play is at work all the time in psychoanalysis. The play element functions continuously to sustain a paradoxical reality where things may be real and not real at the same time. This paradox is what allows the work of psychoanalysis to take place. The concept of play covers different activities with complex interrelations, and general definitions may be misleading. The essential element is the framework that makes the paradoxical reality possible. The logical structure of the play framework is investigated, and the paper clarifies the relations between the play frame, transference and enactment. Play and humour are compared. Spontaneity is the essence of both, and the criterion for analytic validity in both cases is whether they deepen the analytic process. The tragic and ironic aspects of psychoanalysis are related to the intrinsic connection between play and loss. The relation between play and games is discussed. The rule-bound quality of games can block more exploratory kinds of play, but it may be necessary to accept this, in order for analysis to feel safe enough. Clinical material illustrates the importance of the play framework, both in a case marked by prolonged hostile and negative states of mind, and in others where more straightforward playfulness was possible.