The aim of the present study was to investigate the serum total protein (TP), total sialic acid (TSA), lipid-associated sialic acid (LSA), LSA/TP, and LSA/TP values in type 2 diabetes mellitus (DM) patients. Two study groups (healthy controls and type 2 DM subjects) were examined. For the type 2 DM group, 120 patients (60 females and 60 males) who had been diagnosed and treated for type 2 DM in the Yuzuncu Yil University Hospital, Van, Turkey, were selected consecutively. Forty healthy individuals (20 females and 20 males) were selected from hospital staff and other outpatient clinics to serve as the control group. They were matched for age, sex, body mass index, and smoking status. None of the participants had taken vitamin or mineral supplements for at least 2 weeks before sampling. To determine serum glucose, TP, TSA, and LSA levels, blood samples were drawn after all of the subjects fasted overnight. It was found that diabetics had higher TSA, LSA, TSA/TP, and LSA/TP levels than controls. However, the TP levels were not significantly different between the groups. Our results showed that TSA, LSA, TSA/TP, and LSA/TP have interactive connections with DM. These parameters can be used as a diagnostic index for patients with DM. J. Clin. Lab. Anal. 17:124-126, 2003. (C) 2003 Wiley-Liss, Inc.