The aim of this study was to analyse whether preoperative serum levels of CEA and CA 15-3 correlate with oestrogen (ER) and progesterone (PR) receptor rate and MIB-1 score in elderly (>65 years) women with breast cancer (BC). Data from a series of 349 women (median age 61 years, range 26-89) with pT1-2 BC who underwent curative surgery were reviewed. Patients were divided into two groups: Group A, 237 (60.2%) women <65 years, and Group B, 157 (39.8%) women >64 years. Size of the tumour, ER, PR, CEA and CA 15-3 preoperative serum levels were higher in older patients, while the MIB-1 rate was lower. In both groups, a significant (p<0.05) inverse correlation between ER and MIB-1 was found, while there was a relationship between MIB-1 and both PG and CA 15-3 only in younger patients. These data suggest that only MIB-1 index should be considered an effective parameter for assessing tumour proliferation.