Mycoplasma bovis is a major pathogen in respiratory diseases of calves and cause an excessive economic loses. The current study was a goal to diagnoses bovine Mycoplasma and chiefly M. bovis from an outbreak of pneumonia in calves that occurred in Mosul city and mainly in Gogjaly village. Forty-two lung samples were collected from slaughtered and dead pneumonic calves in seven herds of imported calves. Extraction and amplification for DNA were conduct from all samples for diagnosis of Mycoplasma and M. bovis by PCR technique. The results have recorded the presence of Mycoplasma in 88.1% of examined lungs and M. bovis was diagnosed in 86.5% of the positive Mycoplasma samples. Finally the present study is the first local study at the moment which diagnoses Mycoplasma in general and mainly M. bovis from pneumonic calves, also according to the results it recommended the use of molecular techniques and principally PCR for the diagnosis of Mycoplasma and M. bovis.