In this case report we are presenting a rare case of primary pulmonary plasmacytoma in a dog in the context of clinical and pathological findings. A six-years-old, female Rottweiler was brought to the clinic with respiratory complaints. The patient was dyspneic and tachypneic, and there were friction sounds on auscultation of the lungs. Laryngeal and tracheal palpation induced severe cough. Lateral and ventrodorsal radiographs of the thorax showed increased opacity in the lungs and loss of cardiac silhouette. Based on clinical and radiological findings, diagnosis of a lung mass was made and surgery recommended. Under general anesthesia, bilobectomy of the right lung lobes by medial sternotomy was performed. Upon cytological and histopathological findings, plasmacytoma was diagnosed.