Background: Since autism detection protocols rely primarily on parental accounts of early symptoms, the use by Spanish-speaking populations of screening tools developed in a different language and socio-cultural context (usually English) might hamper the success of early detection programs. Method: A systematic search in four databases was completed, identifying 59 tools used for ASD detection. Of these, only nine tools had been applied in Spanish-speaking populations, and of those, only five can be considered specific tools for the early detection of autism. Results: Sensitivity detecting autism was generally lower in the Spanish versions of the reviewed instruments, while specificity tended to be equal to or higher than that reported in the original screeners. Conclusions: Heterogeneity and poor methodological rigor of the studies conducted to date emphasize an urgent need for a concerted effort to develop reliable and valid instruments for the early detection of autism in Spanish-speaking populations worldwide.