Introduction. Prevalence of estrogen (ER), progesterone (PgR) and human epidermal growth factor receptors (HER2) vary by age among women with breast cancer (BC). Such variation has a large significance for the prognosis and treatment process. This study characterizes the prevalence of breast cancer subtypes by age in a hospital sample in Poland. Material and methods. The study population included 735 women with BC aged 27–91 years old (ICD-10: C50) and treated in the years 2009–2011 in the Military Institute of Medicine in Warsaw. Subjects were divided into 2 age categories — 27–44 and 45+ — which included 66 (9%) and 669 (91%) women respectively. In each group prevalence of PgR, ER and HER2+ receptors was investigated. Results. In both age groups the most frequent BC subtype was luminal A (hormone dependent BC — with PgR and ER receptor expression) — 27–44 years old — 44% and 45+ years old — 56%. The lowest number of cases in the age group 27–44 was luminal B (triple positive breast cancer) — about 15% of cases and for 45+ age group — HER2+ BC — about 11%. Discussion. Performed research shows relationship between growing age of diagnosis and presence of more desirable features of BC among women aged 55 and more, such as expression of steroid receptors or lack of expression of HER2 receptors, which is a good prognostic indicator for treatment outcomes. In the same time, many studies suggest that more aggressive types of breast cancer (basal-like — triple negative) are more characteristic for younger age groups (under 45 y.o. and younger women in perimenopausal age). Same results have been obtained in own study. Conclusions. A high incidence of BC in older age groups (45+) and more frequent occurrence of aggressive types of BC among younger women (27–44 years old) indicate the need to educate women from both age groups about risk factors and early symptoms of the disease. As we still have not recognized all BC risk factors, education about well-known agents, such as alcohol intake, overweight and obesity, play significant role in decrease of BC incidence and mortality.