Severe ring spots, mosaic, and stunted growth were observed on plantations of sugar beet in Minia governorate. This study revealed that the causal agent is a strain of tomato black ring virus (TBRV). This strain was tested to infect 44 plant species, cultivars, and varieties (belonging .to 11 families). The virus was transmitted mechanically to all tested plants·. Virus activity was lost in infectious sap exposed to 55°C for 10 min. It withstood a dilution of 10^-4 and remained active for 7 days. The partially purified preparation of isolated virus gave one line of precipitate in gel-diffusion test and reacted positively in DAS-ELISA with OD 2.4 while the beet varieties, obtained OD ranged between 1.0 to 2.0. The infected Gazilla and Raspoly beets showed the highest reduction in shoot yield (35%), while Montpianko showed the lowest reduction in root yield (23%). The virus infection had less effect on sugar content in Montpianko and Oskarpoly varieties.