Unilateral diaphragm paralysis is an often not recognised cause of dyspnoea. We present a patient with a unilateral phrenic nerve paralysis treated with diaphragmatic plication. Patient presented with life-style limiting dyspnoea and pulmonary function showed a decrease in FVC when lying down. Since there was no improvement after respiratory muscle training, plication of the hemidiaphragm was performed by a small thoracotomy. The patient improved with regard to respiratory complaints and lung function. Furthermore, we also demonstrate for the first time a significant improvement in exercise capacity with accompanying striking amelioration of quality of life. The patient is now in follow up up for more than 2 years and the impressive improvement in exercise capacity remains present. Surgical treatment of unilateral diaphragm paralysis has been described in case reports and in small series since 1985. Although comparison of the available data is difficult a diaphragm plication seems an effective and safe procedure for patients with symptomatic, acquired unilateral diaphragm paralysis. Improvement of dyspnoea is present in the majority of patients and we even observed an impressive amelioration in exercise capacity. Consequently, it seems appropriate to propose plication to patients with clear symptoms from the moment spontaneous recovery seems unlikely; yet, prospective randomised controlled studies are needed to prove this.