This study describes secular trends in physical growth in Brazil over a period of three decades. The study is based on two comparable national surveys undertaken in the mid-seventies and late eighties. Mean heights at ages 7 and 22 are estimated for three cohorts of males and females born around 1952, 1967 and 1982, respectively. Positive secular trends are found both between 1952 and 1967 and between 1967 and 1982. Modest height gains of around 1.0 cm per decade comparable to those described in developed countries during the second half of the 19th century are observed in the first period (1952-67). Outstanding height increments of around 2.4 cm per decade and comparable only to those described for Japanese children after 1950 are detected in the second period (1967-82). Height increments tending to higher values in the second period are seen for both sexes in the five Brazilian macroregions and in different economic strata. Even so, a large gap still separates the physical growth as observed in the north and northeast regions (and, generally speaking, among the poorest third of the Brazilian population) from the normal growth pattern expected when living conditions are adequate. Substantial income improvements over the seventies plus the continuous progress in the availability of sanitation, health and education services during the seventies and eighties are consistent with the exceptional height gains observed between the cohorts of 1967 and 1982. On the other hand, the tragic performance of the Brazilian economy during recent years plus the evidence that infant mortality rates did not decline in the eighties as they had done in the seventies may suggest a reduction in the speed of the positive trends in growth. If this hypothesis is true, the full development of the genetic growth potential of a large part of the Brazilian population will be postponed to a very remote future.