As a specific measure to assess levels of parental stress is lacking in Spain, the aim of this study was to develop the Spanish version of the Parental Stress Scale (PSS). After translating it from English into Spanish using the forward-backward translation method, it was administered to a sample of 211 first-time parents (105 males and 106 females). A factor analysis was carried out to assess its dimensionality. After refining the scale, we obtained a two-factor solution that accounted for 33.5% of the variance, with the factors Stressors and Parenting Rewards. No gender differences were found either in the scale or in the dimensions. Criterion-related validity was tested by means of correlations with anxiety and depressive symptoms and, with regard to internal consistency, adequate alpha coefficients were obtained for both factors.