To establish the range of diameters of normal extraocular muscles, we used standardized A-scan echography to measure the superior recti/levator complex, medial, lateral, and inferior recti muscles in 38 subjects with healthy orbital tissues. The relationships of age, gender, height, and weight to axial length of the globe were considered. These factors and extraocular muscle diameters were not consistently associated. Our normative data were compared with previously reported studies of extraocular muscle diameter performed with standardized A-scan and contact B-scan echography and computed tomographic scanning.