Biocontrol of plant diseases is undeveloped in Brazil and the classical biological control has not been employed in disease control. There is litle evidence to date that indicates that there are specific microorganisms found in certain geograpical areas that are responsible for controlling a particular plant pathogen. To be succesfull, the antagonist should be able to survive in the new habitat. Therefore, this approach is most promising in situations where the environment conditions can be controlled to favor the growth of the antagonist, as is the case for post-harvest diseases. However, reseraches are required to identify most significant factors interfering with the antagonist growth. Also, there have been studies with different antagonists for the sameplant pathogens, which reinforces the need for exchanging material and for more interactive work. The challenge is to identify in nature the reason for a non-occurrence of a pathogen. If the cause is the action of an antagonist, this information should be available worldwide, through on-line information systems, in order to improve research and use of such a promising control method.