The aim of this study was to investigate the plasma apelin levels in diabetic patients with and without neuropathy. All consecutive diabetic patients who presented for routine follow-up at our outpatient clinic were invited to participate in this clinical study. Forty diabetic patients (20 female and 20 male) and twenty-two non-diabetic control subjects (9 female and 13 male) were included in the study. Neurological evaluations in diabetic subjects were done by nerve conduction studies and evaluated with the Neuropathy Symptom Score. Fasting plasma glucose, HbA1c, lipid and apelin levels were measured in each subject. The mean plasma apelin level was significantly higher in the diabetic patients than in the control subjects (p = 0.026). Apelin levels were statistically similar between diabetic patients with and without neuropathy (p = 0.43). Further, plasma apelin levels were found to be higher in diabetic patients with neuropathy when compared with those of healthy control subjects (p = 0.02). In diabetic patients with neuropathy, plasma apelin levels correlated significantly with diabetes duration (r = 0.5, p = 0.02). We propose that apelin levels in diabetic patients are higher in the presence of neuropathy and longer disease duration, although this might not solely suffice as an indicator for the presence of neuropathy in diabetic patients. Drawing attention to the possible association between the apelinergic system and diabetes mellitus, we believe that further studies with larger samples should be carried out also to investigate the presence of retinopathy and nephropathy.