Size-of-farm data for 1964 were fitted to the function In Y =In a·bX Results showed that the percentage distribution of farms by size classes tends to follow the distribution of an inverse exponential function. Furthermore, empirical size distributions seem to have an underlying stability across time and geographic areas. These features have several applications, one of which is prediction of future size distributions of farms. A method of making such a prediction is illustrated with census data on farm numbers in 1935 and 1964.