Trends and differentials in fertility for three high fertility minority populations -- Southern rural blacks, Spanish surnamed, and American Indians -- are examined for the intervals between 1957-60 and 1967-70. Fertility levels and patterns of differentials within these three minority populations are also compared with those of the urban white majority population. Each sub-group studied had very high fertility levels in the late fifties, and exhibited a rapid decline during the sixties. Demographically, the decline was accomplished by a great reduction in fourth and higher order births, although there are also significant reductions in the rates of second and third births. Fertility declines at similar rates for the poorly-educated as well as for the well-educated and for the poor as well as for the more affluent. Differentials in fertility within these populations are also examined. For both the American Indian and Spanish surnamed, there continues to be a considerable fertility differential by education, with much smaller rates shown by Southern blacks. For all three racial and ethnic minorities, there is a strong inverse relationship between fertility and income. After adjusting for various factors, each of three populations has higher fertility among women marrying in their teens than among those marrying at later ages. Also included in the analysis is husband's occupation and the ethnic status of husbands and wives. Eight tables are provided. (Author/AM)