Objective: In France, a preanaesthetic assessment (PAA) several days prior to hospital admission for a scheduled surgical or diagnostic procedure under anaesthesia, associated with a preanaesthetic visit (PAV) the day before, are compulsory. This study aimed at comparing the benefits of PAA with those of a PAV not preceded by a PAA., Study Design: Prospective, controlled, randomized study., Patients: The study included 296 patients undergoing either a urologic, or ophthalmologic, or ENT procedure, randomly allocated either to a PAA (followed by a PAV) group or a PAV (without previous PAA) group., Methods: The main criterion of comparison was the duration of preanaesthetic hospital stay and the secondary criteria were the incidence of procedure postponements and patients' satisfaction respectively., Results: In the PAA group, the preanaesthetic hospital stay was shorter by 0.4 days (P = 0.001). Out of the 19 postponed procedures (7%), the cause of postponement was a medical one in 15 patients: 13 in the PAV group and 2 in the PAA group respectively (P = 0.009). The PAA was not considered as a constraint by most patients., Conclusion: The PAA shortens the duration of preanaesthetic hospital stay and decreases the incidence of procedures postponed for a medical cause.