Abstract: Respiratory diseases particularly lamb pneumonia is a multifactorial disease involving the interaction between host, etiological agent and environment. The present study was carried out to determine the causative agent of an outbreak of pneumonia in a sheep flock and to establish its pathogenicity and public health importance. The incidence occurred in sheep unit at Madhurikund farm of University (DUVASU), Mathura, Uttar Pradesh, India. At the time of incidence, the population of sheep at the farm was 90. Affected animals were clinically examined and nasal swabs and blood samples were collected from live animals, while morbid materials were collected from dead animals after postmortem examination. The etiological agent was isolated and characterized with conventional microbiological and biochemical methods. Streptococcus pneumoniae was the bacteria isolated from blood, different organs and cerebrospinal fluid. The antibiotic sensitivity revealed resistant to multiple drugs viz., penicillin, tetracycline, erythromycin, chloramphenicol, enrofloxacin and ciprofloxacin. Pathological examination revealed multiple involvements of organs with different degrees of inflammation and haemorrhages of the lower respiratory tract, lungs, liver, heart and kidney. Further, its pathogenicity was established by histopathological examination. In conclusion, presence of multi drug resistant Streptococcus pneumoniae in weaning lambs with the involvement of multiple organs appears to be an emerging zoonotic threat to human particularly in shepherds. This seems to be the first report of isolation of multi drug resistant Streptococcus pneumoniae from outbreak in lambs with multiple organ involvement in India.