Purpose: The purpose of this paper is to examine wage differences between part- and full-time workers distinguishing by gender by using a large Spanish matched employer-employee data set and an econometric decomposition that permits to decompose wage differences by quantiles of the wage distribution. Design/methodology/approach: The research is based on cross-section matched employer-employee microdata from a large representative survey (the Encuesta de Estructura Salarial) which is carried out with a harmonised methodology common to all European Union member countries and that has been designed specifically to provide reliable evidence about characteristics of the wage distribution such us wage differentials associated with the type of working time. From a methodological point of view, the econometric decomposition technique proposed recently by Fortin et al. (2011) to decompose wage differences between part-time and full-time workers by quantiles of the wage distribution is applied. This methodology has the advantage over similar techniques that provides a detailed decomposition of wage differentials and has not been used before to examine the wage impact of part-time jobs.