Based on the common study design, protocol, and laboratory techniques used by the Lipid Research Clinics (LRCs), the study reported here compared the adult study populations examined by the U.S. LRCs and the LRC located in Jerusalem, Israel. A number of 2388 residents of Jerusalem were contrasted with 6528 examinees of the U.S. LRCs regarding their plasma lipid and lipoprotein cholesterol distributions. Marked differences between the U.S. and Jerusalem LRCs were observed in the plasma levels of lipids and lipoprotein cholesterol fractions. Mean total cholesterol concentrations were 2-8% higher in the U.S. compared to the Jerusalem sample. Low density lipoprotein cholesterol levels were higher by approximately 5-15% in the U.S. LRCs, a phenomenon more marked in men than women and in older compared to younger study participants. High density lipoprotein cholesterol values were also higher in the U.S. compared to the Jerusalem LRC, by approximately 10-14% in men and women. These differences were also more pronounced in older compared to younger participants. By contrast, median plasma total triglycerides (and by implication very low density lipoprotein cholesterol) were higher in the Jerusalem compared to the U.S. study participants. This difference ranged from 10-21% by age and sex. The correlations between the plasma lipid/lipoprotein measurements were similar in the two study populations. Only the degree of linear association between plasma total triglyceride and very low density lipoprotein cholesterol was different between the U.S. and Jerusalem, with a correlation coefficient of greater magnitude in the latter. Employing common cutpoints to define dyslipoproteinemia (DLP) observed differences in plasma lipid/lipoprotein distributions determined differences in the frequency of DLP categories between the U.S. and the Jerusalem samples. Higher proportions of Type IV and hypo-HDL were observed in Jerusalem compared to the U.S. By contrast, fewer individuals were classified as Type IIa, Type IIb, and hyper-HDL in Jerusalem relative to the U.S.