This paper is concerned with the measurement of aggregate growth rates, where the aggregation is over time. The paper demonstrates that any mechanical procedures for computing aggregate growth rate has welfare implications, and value judgments implicit in various commonly used procedures are not appealing. A new procedure suggested in the paper captures all the essential properties of a welfare function. The methodology of the paper is applied to an analysis of growth rates of per capita GNP of 83 developing countries during the 1970–1987 period.