The reforms contained in Act 1/2015, of March 30th, have entailed substantial changes in the enforcement of criminal judgements particularly regarding the penalty of deprivation of liberty. To such effect, the aim of the study that follows is to analyse the main reforms. Firstly, we focus on the «enforceable title», integrated by the diverse activities intended to promote the material enforcement of the penalty, the suspension or the modification of the enforceable title and the termination of the enforcement. Secondly, we study what we call the «material enforcement», whose objective is the strict fulfilment of the penalty. [ABSTRACT FROM AUTHOR]