A total of twelve seronegative sheep, against infectious bovine rhinotracheitis (IBR), bovine viral diarrhoea (BVD) and parainfluenza-3 (PI-3) and peste des petits ruminants (PPR) viruses were randomly divided into four groups (each group consists of 3 sheep). The first group, received simultaneous vaccination with pneumo-3 and inactivated PPR vaccines, while the second group received pneumo-3 vaccine and after 2 weeks that received inactivated PPR vaccine. The third group received firstly the inactivated PPR vaccine, then received inactivated pneumo-3 vaccine after 2 weeks, while, the fourth group was kept as non-vaccinated control group. All tested animals remained clinically normal throughout the whole experimental period. Very satisfactory serological responses were detected in animals, simultaneously vaccinated with both vaccines. No differences were detected in serum neutralizing antibody titres against IBR, BVD, PI-3 and PPR viruses, in sheep which received inactivated PPR vaccine, neither before nor after vaccination with pneumo-3 vaccine. The results clearly indicated the safety and efficacy of simultaneous vaccination of sheep with pneumo-3 and inactivated PPR vaccine without any competition for the response to individual vaccine. Also there is neither synergistic nor antagonistic effect for the two vaccines in sheep.