Respiratory muscle weakness and consequently respiratory dysfunction may occur as well as musculoskeletal problems in patients with neuromuscular diseases. Respiratory complications are the most important cause of morbidity and mortality particularly in chronic and rapidly progressive neuromuscular diseases. Vital capacity is reduced and a restrictive ventilatory pattern is seen in these patients. Due to respiratory muscle weakness; fatigue, breathlessness, secretion retention, recurrent lower respiratory tract infections, respiratory failure, pulmonary hypertension, and acute or chronic corpulmonale may occur in patients with neuromuscular diseases. While respiratory problems may manifest initially during sleep, it also reflect to awake period with progression of diseases. Systematic clinical evaluation of neuromuscular diseases is essential for the detection of respiratory signs and symptoms which are masked because of physical capacity inability of patients in early stage. This review will evaluate comprehensively the assessment of respiratory problems which are encountered in neuromuscular diseases under the headings of history, physical examination, respiratory muscle strength measurements, arterial blood gas analysis, peak cough flow measurements, radiologic evaluation, spirometry and sleep.