This study compares the farm businesses and labor incomes earned by vineyard operators on the same 21 farms in 1958 and 1968. During this period these farm businesses increased an average of almost 50 per cent in size, going from 35 acres and 137 tons of grapes in 1958 to 50 acres and 200 tons in 1968. The labor efficiency on these farms increased an average of 23 per cent in terms of acres of grapes per man and 24 per cent in tons of grapes produced per man. In addition, work units per man went up 17 per cent. These farms also became more specialized, with an average of 89 per cent of the work units allocated to grapes in 1968 as compared with 81 per cent in 1958. Further indication of greater specialization is a 19 per cent increase in the proportion of total farm receipts from grapes.