In the Papal States of the end of the sixteenth century, most female monasteries were mendicant. In doing so, nuns violated many rules of the XXVth session of the Council of Trent: they obviously did not respect enclosure, but also were unable to survive only thanks to their real estate properties, as stated by the chapters 2, 3, and 16 of the De Regularibus et Monialibus decree. This financial situation of convents was addressed for the first time by Clement VIII (1592–1605), who led a broad economic reform all over his territory. How was the economic reform of convents led by Clement VIII applied in the local realities of the Papal States, what were its impacts on nuns, and how did they react to these changes? Based on the letters received by the Congregation of Bishops and Regulars in Rome during the Pontificate of Clement VIII, this article addresses the materiality and the local peculiarities of the economic reform of female convents in the dioceses of the Papal States, highlighting the strategies used by nuns to fight against change, negotiate accommodation, or adapt their daily lives to the new Roman requirements. Much less known and studied than the Tridentine enclosure, the economic reform desired by the same Council of Trent is an equally important change whose impacts durably transformed the daily life and identity of nuns.