An easy and safe method for muscle biopsy is described. The biopsy instrument is an alligator forceps (Weil-Bladesley's conchotome). With this method an adequate amount of muscle tissue can be obtained for both chemical and morphological studies. The method combines the advantage of the "open-surgical" method - sufficient quantity of material - with the advantages of the needle methods - easy to perform, not incapacitating and only slightly uncomfortable for the patient. Out of 959 consecutive biopsies with this method only 19 were impossible to evaluate because of too much artefact or too little tissue.