Purpose: The aim of the present cross-sectional study was to determine the effects of age, sex, and maternal education of monolingual Spanish-speaking preschoolers on both macrostructural (oral narrative quality) and microstructural measures (number of different words, communication units, mean length of utterance in both words and morphemes, and number of conjunctions) of their oral narrative production. Method: A total of 277 monolingual Spanish-speaking Mexican children aged 2;06-5;11 (years;months) and divided into four age groups (ages 2, 3, 4, and 5 years) were asked to retell a fictional story from the oral narrative ability task of the "Evaluación Neuropsicológica Infantil-Preescolar." Results: Appropriate internal consistency and interrater reliability were demonstrated. Pearson correlations between macro- and microstructural measures showed a positive association. A multivariate analysis of variance revealed a main effect for age, but not for sex, maternal education, or between-variables interactions. Partial eta-squared showed that age had a medium effect size on oral narrative quality and the number of different words and conjunctions, with a small effect size on communication units and mean length of utterance in words and morphemes. Hierarchical multiple regression analyses indicated that age explained the largest percentage of variance across the oral narrative measures. Conclusions: The measures found to be most sensitive to the effect of age (number of different words, oral narrative quality, communication units, conjunctions) are also those most easily assessed by clinicians with limited training in linguistics. Results obtained for the number of different words and communication units were similar to those reported previously for English-speaking children.