Purpose The purpose of this study is to investigate diabetes rates among Mexicans 20 years and older living in the United States and Mexico in 2012 and 2016. Methods The national sample was the National Health and Nutrition Examination Survey (NHANES) 2011-2012, NHANES 2015-2016, Mexican National Health and Nutrition Survey 2012 (ie, Encuesta Nacional de Salud y Nutrición 2012 [ENSANUT 2012]), and ENSANUT de Medio Camino 2016 (ENSANUT-MC 2016). Sex, age, A1C testing, and medication use (insulin, oral hypoglycemic agents, and both) were examined among participants. Results Most participants in study were female (50.7%, 53.9%, and 57.2%) and were younger (61 years, 57 years, and 60 years). A1C testing was conducted more in the United States (69.6% and 82.6%) than in Mexico (9.5% and 15.1%). More Mexicans (73.1% and 67.8% vs 54.9% and 54.9%) were using oral hypoglycemic agents, while more Mexican Americans used insulin (12.6% and 11.6% vs 6.3% and 11.1%) and used both insulin and oral hypoglycemic agents (17.1% and 15.8% vs 6.6% and 8.7%). Conclusions By examining and highlighting the diabetes mellitus practices and standardization of A1C testing, providers will be able to better understand and address the rising rates of diabetes in the United States and Mexico while driving practice and policy changes.