The purpose of this paper is to identify the main determinants of time-to-degree in higher education. Our results use retrospective data on a full cohort of first-time entering students who embarked on short and long programs from one university in Spain and who were observed over an eight-year period. The empirical results show that time-to-completion is extremely sensitive to students' abilities and, to a much lesser extent, to socio-economic background, motivation and gender. We also find that students' performance and integration at the beginning of the program reduce the time-to-degree, whereas teaching conditions do not appear to matter.