© 2018 Guilera et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The present study is centered in adapting and validating a Spanish version of the Irrational Procrastination Scale (IPS). The sample consists of 365 adults aged 18–77 years (M = 37.70, SD = 12.64). Participants were administered two measures of procrastination, the IPS and the Decisional Procrastination Questionnaire, as well as the Big Five Inventory, and the Satisfaction With Life Scale. First, the factor and replication analysis revealed that the internal structure of the scale is clearly one-dimensional, supporting the idea that IPS seems to measure general procrastination as a single trait. Second, the internal consistency is satisfactory as is the temporal stability of the IPS scores. Third, the correlations encountered between the IPS scores and other measures of procrastination, personality traits and satisfaction with life are all in the expected direction and magnitude. Finally, consistent with previous research, procrastination is related to age, with the youngest being the most procrastinating group. This study represents the first attempt in adapting and validating the IPS measure of procrastination into Spanish. Results suggest that the Spanish version of the IPS offers valid and reliable scores when applied to adult population.