The purpose of the research was to determine if ASTM Standards used for producing men's underwear satisfy the measurements of males in the U.S.Additionally, this research determined whether or not males in the U.S. are satisfied with the fit of underwear made available to them.The results provided insight into a relatively untapped area of research, men's apparel sizing and men's fit satisfaction.This study employed the use of two data sources:the Size USA National Study and an administered online Men's Fit Survey.A considerable amount of the data was statistically analyzed using SAS and JMP statistics programs.The research aimed to substantiate findings cited in the literature regarding inadequate size standards and consumer's dissatisfaction with the fit of ready to wear clothing produced from these standards.This study further evaluated the effect of ethnic group and age group on a subject's ability to meet ASTM Standards."Proposed" classifications were recommended in an effort to enable a larger percentage of U.S. males to meet size designations (small to 2x-large).In addition, the responses from the Men's Fit Survey were used to assess fit satisfaction of underwear in key locations. This study found that at a 95% confidence level, ethnicity and age of male subjects are significant factors that influence measurements used to produce underwear.In comparing the body measurements of 3,691 male, Size USA subjects to ASTM Standards, results showed that only 3% met size specifications for underpants and 1% met size specifications for undershirts.Using the "Proposed" classifications 75% would meet specifications for underpants and 81% would meet specifications for undershirts.In addition, this study found that of the 205 respondents that were surveyed, at least 70% were dissatisfied with the fit of their underpants while 59% were dissatisfied with the fit of undershirts.