In this paper the relative cost efficiency of Scottish farms is determined, and variables that explain this efficiency by farm type are identified and implications discussed. A panel dataset from the Farm Accounts Scheme (FAS) survey for the period 1997-2004 was used for the estimation. A cost efficiency indicator was measured using a fixed effect panel data regression. Further analysis, to explain the efficiency results, indicated the presence of important farm size and regional effects. However, other variables, whilst statistically significant, did not produce a consistent effect across the different farm types.