This paper discusses the economics of non-owner management of medium and large-scale farms in Argentina. The first section of the paper shows that management by non-owners increases at a diminishing rate with farm size. For equal farm sizes as measured by output, however, large variations in the importance of non-owner management is detected. It is hypothesized that these differences are caused by the relative importance of land versus capital, and labor inputs used in production.The second section analyzes production efficiency of farms with non-owner versus owner management. Non-owner managed farms appear to be more efficient; however, this difference is not statistically significant.