One hundred paediatric, muscle ultrasound examinations performed in the evaluation of suspected neuromuscular disease were reviewed. The results were related to the presence or absence of neuromuscular disease in each child assessed. The group comprised 66 males and 34 females, age range 2 months to 16 years (mean 5.3 years). Scans were graded I-IV, according to muscle echogenicity, using Heckmatt's criteria. Thirty-two children had a final diagnosis of neuromuscular disease. The sensitivity of ultrasound in detecting neuromuscular disease was 78% with 91% specificity. The test was more reliable in the sub-group of > 3 years with a sensitivity of 81% and specificity of 96%. There was a significant difference in disease status, (with and without neuromuscular disease), between children with a normal, grade I, scan and those with an abnormal, grade II, III, IV, image (chi-square, P < 0.001, 95% confidence limits 0.54-0.86). Muscle ultrasound is a specific and sensitive investigation for suspected neuromuscular disease in children.