Local reference ranges of immunoglobulins are required for studies and clinical interpretation. In this study, serum levels of IgA, IgG, and IgM in 914 Iranian healthy adult blood donor volunteers, aged 18-55 years, were measured by nephelometry. Our data showed that serum reference intervals of IgA, IgG, and IgM in subjects were 72-375, 636-1518, and 39-283 mg/dL, respectively. Data analysis showed a significant difference between the male and female subjects only for IgM; thus, the means of IgM in females were higher than for males (p < 0.05). Correlation coefficient r for paired samples showed no statistically significant relationship between age and each Ig (p > 0.05). Comparison of this study with others demonstrated that results are similar; some differences are probably related to ethnic differences. Therefore, our results can be considered as a source of reliable local reference for use in laboratories.