Background: Cardiac autonomic neuropathy (CAN) is the most frequent and clinically important form of diabetic autonomic neuropathy. CAN is associated with increased frequency of other microvascular complications of diabetes mellitus (DM). In this study, we evaluated the prevalence diabetic nephropathy, retinopathy, and peripheral neuropathy, and measured gastric emptying time and bladder emptying time in type 2 diabetic patients with varying degrees of CAN. Patients and Methods: Fifty-three patients with DM complicated by CAN (30 women and 23 men; mean age, 58.8 +/- 9.15 years; duration of diabetes, 13.9 +/- 7.7 years) were included in this study. The patients were grouped according to the degree of CAN as early, definite, and severe CAN. Results: There were significant differences regarding the prevalence of nephropathy, retinopathy, and peripheral neuropathy diagnosed by EMG among those groups (P.05). However, there was no significant difference regarding the prevalence of peripheral neuropathy diagnosed by neurological examination (P>.05), and scintigraphic measurements of gastric and bladder emptying time were comparable among the groups (P>.05). Conclusion: The prevalence of other diabetic microvascular complications increase as the severity of CAN increases in patients with type 2 DM. This study emphasizes the need for an early screening for peripheral neuropathy, retinopathy, and nephropathy in type 2 diabetic patients with CAN, especially with severe involvement. (c) 2008 Elsevier Inc. All rights reserved.