Background/Aim: To clarify the role of the apolipoprotein E (Apo E) phenotype in IgA nephropathy, we investigated its relationship with histological damage and clinical factors. Methods: The subjects were 104 consecutive patients (41 men and 63 women) with IgA nephropathy. The Apo E phenotype was identified by plasma isoelectric focusing and immunoblotting, and the frequencies of Apo E alleles were calculated. Results: The frequencies of the phenotypes and the alleles were as follows: 2/2 = 0, 2/3 = 0.086, 3/3 = 0.654, 2/4 = 0.010, 4/3 = 0.211, 4/4 = 0.010, 3/5 = 0.029, Ε2 = 0.048, Ε3 = 0.817, Ε4 = 0.120, and others = 0.015. There were no significant differences between the IgA nephropathy patients and healthy individuals in the frequencies of Apo E phenotypes and the alleles. However, the Apo E2 phenotype was significantly more common among patients with severe histological damage than in those with mild damage. The serum triglyceride levels were significantly elevated, and the Apo E2 phenotype was significantly more prevalent in patients with severe histological damage as compared with those with mild damage. Conclusion: The Apo E2 phenotype appears to be associated with the severity of histological damage in IgA nephropathy.