As population pressure on land grows rapidly in Kenya, rural farmers have started to intensify land use, which has lef to the emergence of a new maize farming system. The new system is characterized by the adoption of high-yielding maize varieties, the application of chemical fertilizer and manure produced by stall-fed improved dairy cows, and intercropping, especially the combination of maize and legumes. This study aims to explore the determinants of the new maize farming system and its impact on land productivity. We examine not only the impacts of new technologies and production practices but also the impact of the entire new maize farming system by generating an agricultural intensification index based on a principal component analysis. The estimation results show that a decrease in the land-labor ratio accelerates farming intensification, and that the adoption of each new technology and production practice has positive and significant impacts on land productivity. These findings are further supported by the significantly positive impacts of the agriculture intensification index on land productivity.