OBJECTIVE Nonalcoholic fatty liver disease (NAFLD) is closely associated with insulin resistance and metabolic syndrome. Prevalence of NAFLD increases greatly in patients with type 2 diabetes mellitus (T2DM), and it may also increase cardiovascular disease mortality and morbidity. The aim of our study was to investigate the prevalence of NAFLD in T2DM population and to compare the prevalence of coronary heart disease (CHD) and its risk factors between diabetic patients with and without NAFLD in a Chinese population. METHODS A cross-sectional survey was conducted among 560 cases of in-patient T2DM patients from January 2002 to January 2009 in southern China. Patients were divided into two groups (NAFLD and non-NAFLD) and underwent clinical examination, anthropometry, laboratory tests and routine liver ultrasonography. RESULTS Prevalence of NAFLD was 75.18% (421 cases) among all participants, and 285 cases (67.70%) had normal liver function and no symptoms. NAFLD group had higher body mass index (BMI), waist/hip circumference ratio (WHR), alanine aminotransferase (ALT), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C) levels than those without NAFLD (p<0.01). Moreover, the prevalence of CHD was also higher in the NAFLD group (p<0.01), especially in those male patients with elevated plasma ALT. CONCLUSIONS NAFLD is a common condition among T2DM patients. Its occurrence may be related to sex, age, abdominal obesity, dyslipidemia metabolism, etc. and it is associated with a higher prevalence of CHD. Plasma ALT levels may act as a marker.