Nonalcoholic fatty liver disease (NAFLD) is associated with insulin resistance, metabolic syndrome and cardiovascular disease. The purpose of this study was to evaluate the phenotype of Japanese type 1 diabetes with NAFLD. The study population consisted of patients with type 1 diabetes with (n = 25) and without (n = 119) NAFLD who underwent an examination with hepatic ultrasonography. The duration of diabetes, HbA1c, body mass index, basal and bolus insulin doses, urinary albumin excretion, prevalence of carotid artery plaques, and incidence of retinopathy in patients with NAFLD were all significantly higher than in those without NAFLD. Dyslipidemia and hypertension also occurred more frequently in the NAFLD group. Logistic analysis showed that age (P < 0.05), gender (P < 0.05), duration of diabetes (P < 0.05), dyslipidemia (P < 0.05), and the presence of NAFLD (P < 0.05) were independent risk factors for the presence of carotid artery plaque. Multiple regression analysis showed that the rate of urinary albumin excretion was significantly associated with age (P < 0.01), systolic blood pressure (P < 0.05), and the presence of NAFLD (P < 0.01). Our results suggest that the presence of NAFLD in type 1 diabetes may be strongly associated with the progression of diabetic nephropathy and macroangiopathy.