Phrenic nerve palsy is a rare condition but it can lead to disabling dyspnoea. The following are reports of four patients who developed unilateral nerve palsy due to neuralgic amyotrophy and viral infections. They all were males with age ranging from 43 to 62 years. All of them developed acute exertional shortness of breath and were found to have unilateral phrenic nerve palsy. All the patients had radiological evidence of unilateral diaphragmatic paralysis and all of them had clinical neurophysiology assessments which confirmed the presence of unilateral nerve palsy. This was proceeded by viral infections in two patients, the other two patients developed severe shoulder pain typical of neuralgic amyotrophy followed by phrenic nerve palsy which was isolated in one and associated with upper limb weakness in the other. Two of them had diaphragmatic plication, a surgical procedure where the paralysed diaphragm is stabilised surgically so the diaphragm does not paradoxically move into the thorax during inspiration and, therefore, improves ventilation to the affected site. Furthermore, the procedure also favours the healthy diaphragm, which as a result will perform less work. There were good improvements in their symptoms with no significant morbidity. Repeated pulmonary function tests showed clear objective improvements. The other two patients continue to have dyspnoea.