This paper analyzed factors related to adoption of new farm practices by dairy farmers in two Pennsylvania counties in 1962 and 1966. (Of 638 farmers interviewed in 1962, 387 were still operating their farms in 1966.) The dependent variable was an index of 19 recommended farm practices, of which about half were being used in 1962. Twenty-one independent variables were used to measure social participation, personal characteristics, and structural factors of the farm operation. Statistical analysis in 1962 indicated that only four of these 24 variables (residence, farm machinery, participation in farm organizations, participation in agricultural extension programs) were significantly related to the dependent variable. In 1966, the mean index showed an increase of two practices. Four independent variables (age, residence, farm machinery, participation in agricultural extension programs) proved significant in 1966, accounting for 45% of the explained variance in farm practices. (Nine tables are included.) (author/ly)