OBJECTIVE: Despite the highest importance of studying the inferential process in psychotherapy, few systematic studies deal with the ways in which psychotherapists work with the material offered by their patients and construct clinical hypotheses about it. The purpose of this study is to present empirical findings about similarities and differences in the way psychoanalysts from different theorethical orientations and level of clinical experience produce their clinical inferences. METHODOLOGY: The sample includes 20 psychoanalysts selected according to their theoretical orientation (Freudian and Lacanian psychoanalysts) and their level of clinical experience (less than ten years and more than twenty years of clinical practice). They listened to the same tape-recorded first session of psychotherapy and were asked to report their clinical hypotheses, clues, and hunches about the material. They also answered a questionnaire about their inferential work. RESULTS: Freudian psychoanalysts produced more single hypothesis and the same number of combined hypothesis than lacanian psychoanalysts. The level of experience was a factor when it came to producing combined hypothesis, no matter their theoretical framework. 90 per cent of the interviewed made their first clinical inference before the first 9 minutes of the session (regardless of their experience and framework), and agreed on the core themes of the clinical case. CONCLUSIONS: there are similarities and differences in the inferential work according to the theoretical orientation and clinical experience of the psychoanalysts. Their level of experience has a positive matching with their capacity to produce more combined inferences. Most of the clinical inferences are psychological and relational, and they are produced at the very beginning of the session.