Abstract: The gold standard measure for assessing muscular size currently is magnetic resonance imaging; however, it is expensive and not easily accessible. Both anthropometric techniques (AN) and ultrasound (UT) are commonly employed methods to measure muscle size. However, the degree to which these approaches offer similar information has not been examined. The aim of the study was to investigate the relationship between UT and AN measurements of muscle thickness in addition to their comparative reliability. Fifteen males (27±9 years) volunteered to take part in the study and underwent both AN and UT measures, taken to assess their upper arm and upper leg muscle size on separate days a week apart. Correlations between the two measures ranged from r=0.548-0.918 (p<0.05) suggesting a good relationship and thus comparable information. Results showed similar coefficient of variation (CV%) for the upper leg (AN 2.3%, UT 2.4%), but slightly greater reliability for UT results for the upper arm (AN 5.5%, UT 2.8%). It appears that both methods are reliable approaches to measurement of muscle size, though AN likely represents a lower cost and greater ease of use. Researchers should consider this when deciding upon which approach to use in the assessment of muscle size in the absence of gold standard approaches.