Electron microscopy of ultrathin serial sections was used to determine the structure and anatomy of the eriophyid gall mite, Cecidophyopsis ribis, the vector of the agent of black currant reversion disease. The composite picture derived from these studies has determined the location of the food canal, and major internal organs of the mite. Detailed ultrastructural studies on the anterior of suitably orientated mites has also provided detailed information on the geometry and complex structure of three sets of stylets in the feeding apparatus. No evidence was found of structures resembling virus-like particles or of other described plant pathogens in the feeding apparatus and food canal of mites obtained from black currant plants affected with reversion disease. However, little or no food was apparently present in food canal of most mites examined. This is the first detailed report of the anatomy and the ultrastructure of the mouthparts of this important plant pest and vector.