Technical, allocative, and economic input efficiency scores were estimated for an unbalanced panel of Swedish dairy farms, using data envelopment analysis (DEA) and the stochastic frontier approach (SFA). By comparing the results it was concluded that when the entire dairy farm is studied the DEA is more appropriate to use since it does not require any particular parametric form to be chosen. The average DEA technical, allocative and economic efficiency indices were eventually found to be 0.77, 0.57, and 0.43 respectively. The influence of size on the efficiency scores was analyzed and significant evidence indicating a positive relationship between size and efficiency was found. Finally it was concluded that the main challenge facing the Swedish dairy farms is to enhance their cost minimizing skills.