Milton Friedman recently warned that a bias exists when per capita income is used to measure economic growth over a period marked by substantial immigration ["A Bias in Current Measurhag of Economic Growth," Journal of Political Economy, March-April 1974]. Friedman framed his argument in terms of the 1870-1914 immigration experience of the United States. Although immigrant achievements over the period were substantial, noted Friedman, these gains entered negatively in the growth calculation since the below average immigrant skill levels reduced 1914 measured per capita income below what it would have been in the immigrants' absence. Raising the measured growth rate to more accurately reflect immigrant achievements is best accomplished, suggested Friedman, by excluding immigrants from the terminal year income data, although the resulting higher growth refers only to native gains. Note that the presence of diminishing returns suggests another reason for a lower measured growth rate, with interesting implications for other beneficiaries of the immigration whose gains are also not captured in the growth data. Given that the immigrants increase the laborcapital ratio above what it otherwise would have been, the measured growth rate falls below its counterfactual alternative. However, a portion of the additional output consequent upon the immigrants' presence accrues to capital owners in the form of an increased scarcity return to capital. Assuming capital owners are natives, this native gain is as hidden in the growth data as are the immigrant achievements which Friedman focuses on. These native achievements, moreover, are (1) distinct from the capital-labor redistribution that occurs with the immigration, and (2) equivalent to the net gain labor scarce countries realize by importing from labor abundant countries. To the extent that the diminishing returns phenomenon is operative, Frie dman's immigrant exclusion adjustment zeroes directly in on the latter hidden achievements. A total exclusion of immigrant contributions to output would generate a higher terminal year income statistic, but the number would understate the actual native improvement over the period. Were the exclusion to apply solely to immigrant wage receipts, as practicality reasons suggest, then the adjusted per capita income figure would accurately measure native gains over the period, gains partially attributable to the immigration itself.