Overall survival (OS) and relapse free survival (RFS) were studied in 297 patients according to the presence of insulin-like growth factor 1 receptors (IGF1-R). All the patients were surgically treated for locoregional disease in the same institution from January 1986. The median duration of follow-up was 40 months. RFS was better in patients with IGF1-R in their tumors as assessed by actuarial survival (P = 0.014) as well as Cox analysis (P = 0.016). OS was better in IGF1-R positive tumors studied by actuarial (P = 0.007) as well as Cox analysis (P = 0.010). By Cox analysis the other prognostic factors on RFS were estrogen receptor (P = 0.002), progesterone receptor (P = 0.002), axillary node metastases (P = 0.032), histoprognostic grading (GHP) according to the standard of Scarff and Bloom (P = 0.004), and tumor diameter (P = 0.019). The other prognostic factors on OS (Cox analysis) were estrogen receptor (P = 0.001), axillary node metastases (P = 0.010), GHP (P = 0.009), progesterone receptor (P = 0.012), and tumor diameter (P = 0.007). When combining IGF1-R, GHP, and axillary node metastases, it appeared that IGF1-R, GHP, and axillary node metastases had independent prognostic significance. In this prospective study IGF1-R had a prognostic significance on RFS as well as on OS studied by actuarial as well as Cox analysis.