Fish oils rich in omega-3 fatty acids (primarily, eicosapentaenoic and docosahexaenoic acids) have been shown to significantly decrease triglyceride levels, while increasing LDL-C levels in human subjects. Studies suggest that eicosapentaenoic acid (EPA) is responsible for the rise in LDL-C. Therefore, this trial studied the effects of docosahexaenoic acid (DHA) supplementation on plasma lipids and lipoproteins in subjects with Type IIB dyslipidemia (LDL-C 130–220mg/dl). DHA was provided in triglyceride form with no detection of EPA. Twenty-seven subjects were randomly assigned to three study groups: placebo, 1.5g, or 3.0g DHA. The supplements were given for six weeks under double-blind conditions following a six-week dietary and a four-week placebo lead-in period. DHA supplementation was associated with significant reductions in triglycerides for both the 1.5g (-20.9%, p=0.01) and the 3.0g (-17.6%, p=0.01) groups, while no significant change was observed in the placebo group. LDL-C levels increased by 13.6% in the 3.0g DHA group (p=O.01), but there were no significant changes in the 1.5g DHA and placebo groups. Both the 3.0g and the 1.5g DHA groups showed a significant increase in HDL-C (p<0.05). The change in triglycerides was significantly associated with that of HDL-C (Spearman r=0.47, p=0.05). These results warrant further studies with larger sample sizes to observe the effects of low dose DHA supplementation in hyperlipidemic patients.