A virus isolate was obtained from naturally infected philodendron plants grown under field conditions at Giza Governorate. A.R. E. According to symptomatology, host range differential hosts, physical properties, mode of transmis¬sion, serological reaction and electron microscopy, the iso¬lated virus was identified as a strain of cucumber mosaic virus (CMV). The isolated strain of CMV induced chlorotic spots and yellowing on the leaves acompanied with stunting of philo¬dendron plants. The virus has a wide host-range and out of the tested plants, only Chenopodium amaranticolor, C. album and C. cruinoa showed local infection. Thermal inactivation point of this strain was between 60-65°C, dilution-end point was found to be between 10-4 to 105 and longevity in vitro was 48-60 hours. The virus was easily transmitted by sap (90-100%), Myzus persicae (about 80%) in non-persistent manner as well as through cuttings (85%), corms (65%) and cormels (50%). The infectious sap reacted positively with CMV anti¬serum, but not with the healthy one. Electron micrographs showed numerous isometric par¬ticles, 30 nm in diameter.