Among nonelderly adults with diabetes, we compared hospitalizations for ambulatory care-sensitive conditions from 2013 (pre-Medicaid expansion) and 2014 (post-Medicaid expansion) for 13 expansion and 4 nonexpansion states using State Inpatient Databases. Medicaid expansion was associated with decreases in proportions of hospitalizations for chronic conditions (difference between 2014 and 2013 -0.17 percentage points in expansion and 0.37 in nonexpansion states, P = .04), specifically diabetes short-term complications (difference between 2014 and 2013 -0.05 percentage points in expansion and 0.21 in nonexpansion states, P = .04). Increased access to care through Medicaid expansion may improve disease management in nonelderly adults with diabetes.