The survival of the small-farm scctor in the process of agricultural modernization in Latin America has bccn a concern for many authors and institutions. Tt is generally believed that the small-farm seetor is bypasscd in the proeess of agricultural development. The authors analyzc modcrnization of bcany maize cropping systems in Southern Colombia. Priees, production practices and profitability arc cornparcd for 1975 and 1989. Dy means of a production function, the effects of alloeative efficiency, teehnical effieiency and technical change on productivity and profitability are analyzed. The obscrvcd changes refleet very weil the priee trends over the period. Bctwccn 1975 and 1989, total factor produetivity incrcascd by 50%. Dean/ maizc produecrs almost doubled returns to land and labor. Inereased teehnieal efficieney had most effeet on profitability, followcd by teehnical change. Alloeative effieicncy had more impact on yields than on profitability bccausc it was associatcd with high input costs, Considerable opportunities for further productivity incrcases werc identified. Conclusions on the nature of the modernization process are drawn. Implications for agrieultural policy, rcscarch and the role of the small farm in agricultural development are dcrivcd,