Fifteen outbreaks with clinical picture and post- mortem lesions similar to that of rabbit haemorrhagic viral disease (RHVD) were investigated in vaccinated flocks during the period between February and July 2005 at Kafr El-Sheikh Governorate. Twelve representative liver homogenate were positive in haemagglutination test (HA) using human type (O) washed RBCs, with titer more than 1/160. Detection of virus particles by electron microscopy, histopathological findings as well as pathogenicity test , confirmed that the outbreaks were RHVD. The possible role of field rats for the transmission and spread of RHVD among rabbitaries was studied. Cross reactivity and cross protection tests were conducted. These tests proved that the newly emerged RHVD isolates were not closely related to classical local vaccinal strain of RHVD and may be a variant strain.