Sustainable development depends on maintaining the health of the natural resource base. Agroforestry has been recognized as a promising means for combining production with resource conservation. It has been shown that agroforestry can contribute directly to better food security, health and nutrition through improvement of land productivity and services. Agroforestry is increasingly being recognized for its potential to solve problems related to soil fertility and erosion, water management, environmental services and biodiversity. Pests and diseases on agroforestry trees are among the challenges faced while scaling up Agroforestry technologies. Although diversification of tree and shrub species is generally accepted as good, there is a need to assure productivity and sustainability of agroforestry innovations by addressing tree-crop health. This learning material is focused on understanding treeecrop interactions in terms of pests and diseases and developing approaches for the management of ill-health. The principal objective is to familiarize students and trainers with the common tree-health problems in Agroforestry systems. Chapter one provides an introductory note on ill-health of trees and principles of tree health assessment in agroforestry with a few examples of biotic and abiotic factors that affect tree health. Chapter two deals with pests and diseases in Agroforestry. Chapter three draws attention to the contributory factors of ill-health in Agroforestry. It expounds important concepts relevant to the understanding of tree-crop-pest-pathogen interactions. Successful scaling- up of agroforestry technologies depends on how best the systems cope with the changing climate. Thus, chapter four presents some of the issues relevant to Agroforestry that require developments of safeguarding mechanisms. Finally, Chapter five covers ill-health management strategies. lt draws attention on the concepts of ill-health and how to manage health at the species, technology and landscape levels. Many references are drawn from electronic media with the intention that readers and journal resources as well as electronic media for quick information. The exercises and future research recommendations are intended to guide the reader, and should be modified according to prevailing circumstances.