The frequency and pattern of progression or regression of coronary atherosclerosis in contemporary patients with diabetes remain unknown. This study included 605 patients with coronary artery disease (CAD). Two coronary angiographic examinations at baseline and after 2 years were performed. The analysis focused on non-stented segments with diameter stenosis ≥25 %. Atherosclerosis progression (or regression) was defined as a decrease (or increase) in the mean minimal lumen diameter (MLD) in the 2-year angiogram compared to mean MLD in the baseline angiogram of >0.2 mm. Statins were prescribed in 576 patients (95.2 %). The primary outcome was atherosclerosis progression or regression in the 2-year angiogram. One hundred sixty-nine patients (28 %) had diabetes. Diabetic patients had greater reduction of mean MLD in the 24 angiogram compared to baseline angiogram than nondiabetic patients (0.11 ± 0.18 vs. −0.08 ± 0.15 mm, P < 0.001). Atherosclerosis progression was observed in 37 patients with diabetes and 16 nondiabetic patients (21.9 vs. 3.7 %; P < 0.001). Atherosclerosis regression was observed in two diabetic patients and 78 nondiabetic patients (1.2 vs. 17.9 %; P < 0.001). A progression pattern across all coronary segments was observed in 70 patients (41.4 %) with diabetes and 60 patients (13.8 %) without diabetes (P < 0.001). Diabetic patients with a low-density lipoprotein cholesterol ≥70 mg/dl showed more atherosclerosis progression than diabetic patients with LDL cholesterol <70 mg/dl (delta-MLD: 0.12 ± 0.19 vs. 0.08 ± 0.16 mm; P = 0.04). In conclusion, in contemporary patients with CAD treated with moderate-intensity statin therapy, diabetes is associated with the increased risk of progression and decreased probability of regression of coronary atherosclerosis.