A teaching-learning system of practices in Surgery named "Hospital Activity of undergraduates in surgery" has been performed over the last five academic courses in Alicante's Medical School. It is based on the stay and participation of 10 students over a 4 weeks period in the assistance tasks of one of the Teaching Hospital Surgery Department in the areas of: hospitalization, external visits and operating rooms. In order to fulfill the proposed teaching objectives a series of clinical sessions and special practices are performed. The hospital activity of 4 academic courses has been evaluated through the performance of a test addressed to the students and a evaluation using a multiple choice test. This educative method is accepted by the students although there are some aspects susceptible to be modified. A significant increase of knowledge between a pretest and a posttest (p less than 0.05) is observed and a significant absence of lacking of knowledge regarding the cognitive objectives fulfilled. Thus, this model of teaching-learning is valid and applicable in our environment.