Diaphragmatic palsy is a paralytic rise of one or both sides of the diaphragm with impaired movement due to damage to the phrenic nerve and blocked nerve impulses. The following is an overview of how diaphragmatic palsy is diagnosed clinically. The clinical manifestations in cases of bilateral complete diaphragmatic palsy are characteristic and a clinical diagnosis can be made based on severe clinical dyspnea and abdominal paradoxical breathing, combined with the underlying disease that has the potential to cause diaphragmatic palsy. In cases of unilateral diaphragmatic palsy, especially incomplete palsy, the diagnosis is usually asymptomatic clinically and requires ancillary tests to clarify the diagnosis. Tests that are useful in confirming the diagnosis of diaphragmatic palsy include X-ray chest fluoroscopy and electromagnetic stimulation of the phrenic nerve to evoke action potentials and transdiaphragmatic pressure measurements.