Apolipoprotein AV (APOA5) is an important determinant of plasma triglyceride concentration. This study aimed to investigate the relationship of an amino acid substitution at position 182 (G182C) of the apolipoprotein AV (APOA5) gene with triglyceride concentration in a Taiwanese population. This study enrolled two cohorts: non-diabetic subjects (112 males and 89 females) aged 50.3+/-11.0 years (mean+/-sd) and diabetic subjects (106 males and 96 females) aged 62.1+/-10.3 years. The relationship between the G182C polymorphism (rs 2075291) and plasma triglycerides was examined. Demographic and metabolic parameters including age, sex, body mass index, fasting plasma glucose and total cholesterol were also obtained. The G182C polymorphism was a determinant of plasma triglycerides in both non-diabetic (P=0.022) and diabetic (P=0.003) groups, independent of age, gender, fasting plasma glucose, body mass index and total cholesterol. In the diabetic group, this genetic polymorphism interacts significantly (P=0.032) with fasting plasma glucose concentration on plasma triglycerides after adjustment for age, sex, body mass index and total cholesterol. In conclusion, the G182C polymorphism of the APOA5 gene affects plasma triglycerides in both non-diabetic and diabetic populations. The observed interaction of gene and glycaemic control further indicates a multifactorial nature of clinical phenotypes in subjects with Type 2 diabetes.