Despite its importance, studies involving developmental delay remain low in the last 10 years in Latin. The objective of the present study was to estimate and compare the prevalence of developmental delay during 2019-2022 in Mexican children under 5 years of age. This was a cross-sectional study carried out in Nuevo Leon, Mexico (n = 2,951). Developmental delay was measured with the "Prueba de Desarrollo Infantil" screening test. Point prevalence and 95% confidence interval (CI) were estimated globally, per area, and per year. The association of sex and children's age to developmental delay was evaluated with binary logistic regression analysis. The prevalence of developmental delay was 42.1% (95% CI: 40.3-43.9). An upward trend was identified; prevalence reached 76% at the end of the study period. Alarm signs and language registered the highest prevalence. Being male doubled the chances of developmental delay (odds ratio 2.2, 95% CI: 1.9-2.6), and having 2.0-2.9 years increased seven times the possibilities of developmental delay (odds ratio 6.7, 95% CI: 5.3-8.7). Findings highlight the challenge that the health sector faces to stop and reverse the developmental delay statistics.