BACKGROUND: Prediabetes has been associated with increased all-cause and cardiovascular mortality. However, no large-scale studies have been conducted in Mexico or Latin America examining these associations. METHODS: We analyzed data from 114 062 adults without diabetes (diagnosed or undiagnosed) from the Mexico City Prospective Study. Participants were followed until January 1, 2021, for cause-specific mortality. We defined prediabetes according to the American Diabetes Association (ADA; HbA1c ≥ 5.7% to <6.5%) and the International Expert Committee (IEC; HbA1c ≥ 6.0 to <6.5%) definitions. Cox regression adjusted for confounders was used to estimate all-cause and cause-specific mortality rate ratios (RR) for deaths occurring at ages 35 to 74 years associated with prediabetes. RESULTS: After median 18.4 (IQR 17.6-19.7) years of follow-up, individuals with prediabetes had higher risk of all-cause mortality at ages 35 to 74 compared to those without prediabetes (RR 1.13 [1.07-1.20] for ADA-defined and 1.27 [1.17-1.38] for IEC-defined prediabetes), as well as higher risk of cardiovascular (RR 1.23 [1.11-1.37] and 1.44 [1.24-1.67], respectively), renal (RR 1.33 [1.06-1.66] and 1.62 [1.18-2.23], respectively), and acute diabetic deaths (RR 2.62 [1.75-3.93] and 3.42 [2.09-5.61], respectively). The absolute excess risk associated with ADA-defined prediabetes at ages 35 to 74 accounted for 7% of cardiovascular, 9% of renal, and 31% of acute diabetic deaths. IEC-defined prediabetes accounted for 4%, 5% and 14% of cardiovascular, renal, and acute diabetic deaths. Prediabetes-associated excess mortality risks were, at least in part, explained by adiposity. CONCLUSION: Prediabetes is a significant risk factor for all-cause, cardiovascular, renal, and acute diabetic deaths in Mexican adults. Early identification and timely management of prediabetes among individuals at risk of this condition could reduce premature mortality in this population.