A cucumber mosaic virus isolate was found to be associated with mottle crinkle and severe mosaic disease of Egyptian henbane (Hyoscyamus muticus L.). The virus has been characterized as an Indian isolate of cucumber mosaic virus (CMV) based on non-persistent transmission by aphid, presence of 28-nm isometric particles, capsid protein of 26 K and single-stranded tripartite RNA genome with a subgenomic RNA (RNA 4). There was no evidence of satellite RNA genome. The isolate showed a strong serological relationship with S and A strains of CMV (CMV-S and CMV-A) in double diffusion test. A band of the 26 K capsid protein was also detected by Western blot analysis using antibodies specific to CMV-S.