This paper exploits a national university reform, introduced in Italy with an exogenous timing and an unintended delay of treatment scheme, to identify the impact on higher education participation of shortening the degree duration of the first-tier university studies. Using a degree-specific universal database, we estimate that enrolment increased on average between 10.3 and 10.9 percentage points in the first year of the reform, and between 27.3 to 29.3 p.p. in the subsequent steady state. Such increase did not occur at the expense of deteriorating retention and on-time graduation rates. These results are of high policy relevance in two ways: first, because they indicate that the steady state cost-elasticity of participation to higher education is higher than what previously indicated by short-run estimates; second, because the enrolment gains are not suggested to be achieved at the expense of enlarging participation to insufficiently-skilled students.