Egypt is endemic for Newcastle disease virus (NDV) with continuous long-lasting outbreaks causing
significant losses in the poultry industry. This study was designed to isolate and identify NDV from
different localities in Egypt (Giza, Gharbiya, Kalyobiya, Sharkia, Menofia, Fayoum and Minia) among
chicken flocks and estimate its virulence using Mean death time (MDT) and intra-cerebral pathogenicity
index (ICPI). Forty samples were collected from chickens either alive or dead showing clinical findings
and post-mortem lesions characteristic for NDV. Virus propagation in embryonated chicken eggs was
confirmed by hemagglutination (HA) test and identified by hemagglutination inhibition (HI) test using
NDV specific antiserum. The results indicated that 23 (57.5 %) out of 40 samples were NDV positive.
The isolate from Giza was velogenic with MDT of 48 hours and ICPI of 1.625. While the isolate from
Qualubiya was lentogenic with MDT of 96 hours and ICPI of 0.4375.These findings provide data on
biological pathotyping of NDV in chickens in Egypt and emphasize importance of NDV surveillance
for improving of strategies for the control of the disease