Increasing demands for residue-free fruits, changes in regulation and a decreasing number of available synthetic fungicides favour growth of the biocontrol products market. These products include naturally occurring beneficial microorganisms which are used to control plant diseases. This chapter assesses the current status of biocontrol techniques and their practical application. As the chapter shows, their main modes of action are competition, induced resistance, hyperparasitism and antibiosis. The chapter reviews the use of biocontrol agents for control of major fruit tree diseases such as fireblight, post-harvest fruit rots, brown rot, apple scab, European canker and pear brown spot. Commercial biocontrol products are registered mainly for control of fireblight in pome fruit and of post-harvest fruit rots in pome fruit and stone fruit. The chapter concludes by looking at future developments in the subject.