Purpose: This article evaluates the Spoken Knowledge in Low Literacy in Diabetes (SKILLD) questionnaire, a measure of essential knowledge for type 2 diabetes self-management, after it was modified for English- and Spanish-speaking Mexican Americans. Method: We collected surveys (SKILLD, demographic, acculturation) and blood for A1C analysis from 72 community-recruited participants to analyze the SKILLD’s internal consistency, interrater reliability, item analysis, and construct validity. Clinical experts evaluated content validity. Results: The SKILLD demonstrated low internal consistency but high interrater reliability and content and construct validity. There were significant correlations in expected directions between SKILLD scores and acculturation, education, and A1C and significant differences in SKILLD scores between and within groups after an educational intervention and between high- and low-acculturated participants. Conclusion/Implications: The SKILLD generates useful information about Mexican Americans’ diabetes knowledge. Lower SKILLD scores suggest less diabetes knowledge, lower health literacy, and participants’ difficulties understanding items. Further modifications should improve use with low-acculturated Mexican Americans.