The present study was conducted to study the immunomodulatory effect of combined of extract of propionobacterium and E.coli lipopolysaccharide (inmunair 17.5) to enhance the immune response of rabbits to rabbit haemorrhagic disease virus (RHDV) vaccine. Forty New Zealand rabbits aged 2 months with average weight 1.5-2 kgs were divided into 4 equal groups. Group (1) was vaccinated with RHDV vaccine and the immunomodulator, group (2) was only vaccinated with RHDV vaccine, group (3) was received the immunomodulator only and the last
group was kept as non-vaccinated, no-treated control. The results revealed that three days oral administration of the immunomodulator under test at time of RHDV vaccination had an improving effect on both humoral and cell mediated immune response of rabbits to RHDV vaccine. Results obtained by challenge test come in harmony with serological test