Ill-fitting bras and insufficient breast support can lead to the development of musculoskeletal pain and inhibit women participating in physical activity. This study aimed to systematically determine the best method for women to independently choose a well-fitted bra. The bra size of 104 women (mean age=43.5±13.2 years; average bra size=12DD; band size range=10-24, cup size range=A-G cup; Australian sizes) was determined through self-selection and bra size measurements. This was compared to the "correct bra size" as determined by professional bra fitting criteria, which were also used to assess the bra fit of each participant's own bra. Eighty-five percent of the participants were found to be wearing ill-fitting bras and the bra sizes determined by self-selection or using bra-sizing measurement systems were significantly different to the correct bra size (p<0.001). Therefore, women were found to have a poor ability to independently choose a well-fitted bra, which was not improved by trying on several bras or using bra-sizing measurements. Education of professional bra fitting criteria may offer medical practitioners and allied health professionals a simple strategy to improve the ability of their female patients to independently choose a well-fitted bra.