Pneumonic pasteurellosis is the most common economically significance infectious diseases of ruminants and predominantly caused by Mannheimia haemolytica, Bibersteinia trehalosi and Pasteurella multocida. However, M. haemolytica has been recognized as the principal cause of pneumonic pasteurellosis in sheep. Although yearly vaccination is carried out using inactivated P. multocida biotype A, pasteurellosis is still reported. This suggests the need for further research into the species and strains responsible for the disease, which is vital evidence for inclusion and development of a multivalent vaccine. With the aim of molecular detection and antibiogram of P. multocida and M. haemolytica isolates, a cross sectional study was conducted from January 2021 to April 2022 in four selected districts of South Wollo. Based on purposive sampling method, 154 deep nasal swab samples were collected from suspected pneumonic sheep for bacteriological analysis. The result revealed that the overall species recovery rates were 47 (30.52%). Out of 47 isolates, 41 (26.62%) of the isolates were M. haemolytica and 6 (3.90%) were P. multocida. Further molecular analyses of the isolates were conducted using primers targeting PHSSA and Rpt2 genes and revealed, 7/41 (17.07%) isolates of M. haemolytica were positive for PHSSA gene and negative for Rpt2 gene. PCR assay targeting capsular biosynthesis (capA) gene of P. multocida isolates were not detected rather 4/7 (57.14%) of PHSSA gene positive M. haemolytica isolates showed non-specific band size around 650 bp different from expected value. Accordingly, M. haemolytica was primary agent for sheep pneumonia in the study districts. Antibiotic susceptibility test result indicated that M. haemolytica isolates were (100%) susceptible for ampicillin and gentamycin. Hence, they were most effective drugs of choice. However, amoxicillin and erythromycin were (100%) resistant and completely inactive against the isolates.