The aim of the study was to evaluate mammography in detecting and staging of invasive lobular carcinoma (ILC) in order to assess the performance and impact of observer variability. Forty-two cases of ILC were retrospectively evaluated twice by two breast radiologists. Mammographic performance as well as intra- and interobserver variations was evaluated. Thirty-five percent to 37% of the cases were understaged. The largest differences between radiologists were found in the breast imaging reporting and data system (BIRADS) classification and staging performance. These results can have serious influence on patient management.