The need to increase crop production on sustainable basis is crucial in the tropics because of poor soil fertility as characterised by low nitrogen and phosphorus status. Agroforestry entails inclusion of woody perennials (trees and shrubs) in a diversified and sustainable land-use system. Use of nitrogen-fixing trees and shrubs (NFTs) in agroforestry systems is specifically to conserve the production potential of such systems due to the inherent ability of NFTs to improve the nutrient status of the soil. Appropriate manipulation and management of the micro-symbiont and macro-symbiont enhances biological nitrogen fixation (BNF) in an agroforestry system that incorporates NFTs as tree/shrub components. This paper highlights the technologies available for ensuring optimal exploitation of BNF in the agroforestry context and also points out some of the misconstructions about nitrogen-fixing symbioses.