Investments made to improve the educational level of the population are beneficial for the society. Nevertheless, in order to reap a considerable part of these benefits, there must be a fit between the trained human capital and the needs of the labour world. If this does not happen, an entirely undesirable educational gap will occur. This gap can be clearly demonstrated in situations of both overeducation and undereducation. In view of this fact, the objective of the study herein presented, is to measure the possible educational gap existing for university graduates when they access their first job as well as to establish the possible determinants of this situation. In the analysed context, Spain, the results obtained show that a situation of overeducation exists, given that Spanish graduates initially take on jobs that are in a category inferior to what would correspond to their education. (Contains 3 tables, 2 charts and 5 notes.)