Baruffaldi and Landoni [12] established that the prob- ability of return increases with the decrease in the period of stay abroad, a more temporary professional situation and the reason for the departure not being related to better job opportunities. According to the figures obtained in this study, the Spanish researchers stayed abroad over 3 years on average, in agreement with previous studies [10]. Further, the majority of them worked in a temporary position (75% hold a post- doctoral position or lower) and the main reason for departure was the continuation and progress of their research careers.