Tomato bushy stunt virus induces in the cells of systemically infected Gomphrena globosa the formation of two different types of inclusions: multivesicular bodies (MVBs) and dense granules (DGs). Their origin, relationships with cell organelles, and development throughout the course of infection were investigated by selective staining, cytochemistry, and serial sectioning. Although they originated from peroxisomes, possibly with a contribution of endoplasmic reticulum for the vesicular component, the MVBs were strongly associated with chloroplasts. The chloroplasts were, in turn, highly modified, with flask-shaped invaginations opening toward the MVBs. By contrast, the DGs were not preferentially associated with particular cell components, and appeared to consist mainly of protein. The meaning of the association between MVBs and chloroplasts and the possible role of MVBs and DGs in the infection process are discussed.