The aim of this study was to analyze the psychometric properties of the widely used general procrastination, decisional procrastination, and adult inventory of procrastination scales in both undergraduate and adult Polish populations. Polish versions of these scales were filled out by 390 student and 513 adult participants. Principal component analysis indicated one-factor structure for each scale. The pattern of loadings was congruent between student and adult samples. The item-total correlation coefficients were adequate in each sample, with higher Cronbach's alpha values in adults compared to students, who reported higher procrastination scores in general procrastination and decisional procrastination scales. Confirmatory factor analysis showed that the unidimensional model emerged as the best fit when the three scales were considered together. The results of the study suggest that Polish versions of the three procrastination scales are effective and reliable and contribute to the international debate about the dimensionality of procrastination.