Electron microscopic examination of leaf dip preparations made from cole (Brassica oleraceaL. var. acephala), Chenopodium amaranticolorCoste & Reyn., radish (Raphanus sativusL.), mustard(Brassica albaBoiss. Rabenh.), bean (Phaseolus vulgaris L.)and Gomphrena globosaL. plants infected with cole latente virus (CLV) demonstrated consistently the presence of slender rods. These particles, considered as CLV, were about 15 mµ wide and 650 mµ in normal length (NL). The NL was determined in a series of comparative measurements using turnip mosaic virus (NL = 750 mµ) as a standard. Morphological characteristics of CLV permit its inclusion in the potato virus S group, in Brandes' system of classification of elongated plant viruses. Thin section profiles of root and leaf tissues, from CLV-infected cole, showed the frequent occurrence of fibrillar aggregates in the cytoplasm. The particles component of these aggregates were identified as CLV in situ due to the constant association with the infection and their mophological similarities with the particles found in leaf dip preparations. CLV-particles appeared with their longer axis laying side--by-side within these aggregates, often forming a spiral arrangement. Vesiculated areas were occasionally seen in the cytoplasm, with virions in or around them. Virus particles were found in most of the examined cells, except within the tracheids and sieve tubes in the leaf, and within the meristematic zone, in th root. Besides these abnormalities, no other remarkable changes in normal cell structure could be noticed, in agreement with the lack of external symptoms.