Helcococcus ovis is a newly established species in the genus Helcococcus. The clinical significance of this organism in sheep has not been reported. In the current report, isolation of H. ovis from a 6-month-old mixed-breed ewe lamb that died of respiratory disease is described. Pathologic examination revealed severe, focally extensive, chronic necrotizing pleuritis with intralesional coccobacilli and mild, multifocal, subacute mucopurulent bronchopneumonia, indicating a bacterial etiology. A Gram-positive bacterium was isolated in heavy growth from the lung tissue. DNA sequence analysis on the 16S rDNA gene demonstrated that the isolate was H. ovis. To the authors' knowledge, this is the first report of isolation of H. ovis associated with infection in sheep with pleuritis and bronchopneumonia.