Plant-parasitic nematodes cause cocoa yield losses, a sudden death of trees and retardation of seedling growth in nurseries. This chapter explains the hidden nature and the masking effects of these nematodes and how these have led to erroneous control measures. The chapter describes the nematode pests associated with cocoa and the symptoms of damage. It also addresses several available control options and outlines how nematode management is essential in order to reduce crop losses and to ensure self-sufficiency for food and industrial raw materials. The chapter finally looks ahead to future research in this area and provides additional reading for those interested in researching further.