OBJECTIVE The aim of the present investigation was to evaluate the influence of serum triglycerides (TG) on other plasma lipids in patients to be treated for dyslipidemia. METHODS Lipid profiles of a cohort of 801 patients (487 males and 314 females) aged 57 +/- 9 years (mean +/- SD) were evaluated. Patients were stratified according to their plasma lipid levels. They were divided into various groups on the basis of serum TG (> or = 150 or < 150 mg/dL) and high-density lipoprotein cholesterol (HDL-C) (> or = 40 or < 40 mg/dL). RESULTS Patients with TG > or = 150 mg/dL had a higher total cholesterol and lower HDL-C levels compared with those with TG < 150 mg/dL, (p < 0.001). Patients with HDL-C < 40 mg/dL had a lower serum total cholesterol and higher TG compared with those with HDL-C > or = 40 mg/dL (p = 0.011 and p < 0.0001, respectively). In all patients as well as in the subgroups, an inverse correlation between TG and HDL-C was found (r = -0.377, p < 0.001). CONCLUSIONS Although, the metabolic pathway for TG and HDL-C is closely linked, an inverse correlation between TG and HDL-C levels seems to exist in the entire sampled population. This correlation also appears to persist in fasting patients with low levels of TG.