The technical efficiency in milk production of dairy farmers who were cooperative members was compared with that of dairy farmers who were not cooperative members. No statistically significant difference was found between the two groups. However, differences among farmers belonging to different dairy cooperatives were significant. In addition, socioeconomic characteristics such as operator’s education; years of dairy experience; herd type; location of the farm; type of milking system; and per cow inputs of concentrate feed, forage, and labor were significant factors in explaining differences in the technical efficiency of dairy farmers.