Technical and scale efficiencies are estimated for organic and non-organic dairy farms in the United States using an input distance function approach. A multinomial logit analysis is used to categorize the farms by technology. Large conventional farms outperformed smaller farms in most technology / organic / non-organic categories. There was high variability in net returns among the organics so that they did not differ significantly from the large conventional farms. The largest conventional non-organic operations and conventional organic operations tended to have the higher technical efficiencies.