The aim of this study was to present mammography and ultrasound features, and accuracy, in 348 young women (under 35 years old) with breast cancer, and to determine whether such features could be correlated with pathological and biological factors. We performed a retrospective review of the radiological, pathological and biological features of women under 35 years old with breast cancer who were seen in our institute between January 2000 and December 2002. A total of 348 women were analysed. The sensitivity of mammography was 84.9% and that of ultrasound was 88%. There is a statistically significant positive correlation between the high sensitivity of ultrasound and the histology type (P=0.004) as well as the expression of PgR (P=0.01). Also, there is a correlation between the sensitivity of mammography and the histology type (P=0.004). Microcalcifications are associated with age (P=0.05) and overexpression of HER2/neu (P=0.007). Ultrasound may be the appropriate initial imaging test for symptomatic young women, and mammography may be useful in confirming the features, although there was no significant difference in the accuracy of the two tests. Histological and biological profiles may be correlated with imaging sensitivity.