Plasma activity of the platelet-activating factor acetylhydrolase (PAF-AH) plays an important role in inflammation and atherosclerotic process in chronic diseases. We aimed to evaluate the levels of PAF-AH activity and their association with the metabolic profile and chronic complications in patients with type 1 diabetes. The study included 118 outpatients (54 males) aged 27.1+/-11.3 years with disease duration of 12.3+/-8.5 years with (n=38) or without (n=80) diabetes complications and 96 control subjects (48 males) matched for age, gender, body mass index and smoking habits. The serum levels of PAF-AH activity were higher in patients either with or without chronic complications (16+/-5.3 and 14+/-5.4 nmol/(min mL), respectively) than in controls (13+/-5.1 nmol/(min mL), P=0.02). In the total population, PAF-AH activity was correlated with age, HDL-cholesterol, total cholesterol and LDL-cholesterol. In patients, PAF-AH activity was correlated with age, HbA1c, uric acid, HDL-cholesterol, cholesterol, LDL-cholesterol, cholesterol/HDL-cholesterol ratio and the LDL-cholesterol/HDL-cholesterol ratio. It is concluded that PAF-AH plasma activity could be a novel candidate for low-grade inflammatory marker in patients with type 1 diabetes.