This paper examined sustained competitive advantage for a sample of 377 Kansas Farm Management Association farms with continuous data from 1988-2007. Technical, allocative, scale and overall efficiency indices were calculated for each farm and year. Approximately 30 percent of the farms exhibited significantly above average overall efficiency levels. These farms had a competitive advantage. Conversely, approximately 28 percent of the farms exhibited significantly below average overall efficiency levels or had a competitive disadvantage. The farms with a competitive advantage were significantly larger in terms of value of farm production and acreage, had significantly lower expense ratios and significantly higher profit margins.