This study attempted to examine the effect of a functional catalase gene polymorphism, CAT -262C>T, on sodium-lithium countertransport (Na-Li CT) activity, insulin resistance determined as the homeostasis model assessment index (HOMA-IR), blood lipid parameters (cholesterol, triglycerides, low density lipoprotein cholesterol, high density lipoprotein cholesterol, apolipoprotein B, apolipoprotein A-I) and their response to atorvastatin, in previously characterized Greek dyslipidaemic patients and normolipidaemic controls. Putative associations were examined by running univariate analyses with a general linear model, using age, sex, smoking and hypertension as covariates. While no statistically significant associations were detected between the CAT -262C>T polymorphism and either baseline values or their modulation by atorvastatin in the patient group, HOMA-IR values were significantly (p=0.028) lower among CAT -262CC controls compared to their T allele carrier counterparts. A trend towards higher plasma triglyceride values among CAT -262CC genotypes was also detected, in both dyslipidaemic patients and normolipidaemic controls.