Cancer is rare during pregnancy, but breast cancer is the second most common cancer in pregnant women. Pregnancy-associated breast cancer (PABC) is defined as breast cancer that occurs during pregnancy or within one year of delivery. Five cases of PABC occurring during the second and third trimester of pregnancy managed at the University Hospital of Vienna during the year 2005/2006 are reported. A review of the available literature is also presented. Five patients were diagnosed with PABC which was detected in completely different weeks of pregnancy. In two women, the diagnosis was made during the second trimester of pregnancy and in three during the third trimester. The treatment depended, among other things, on the gestational age at diagnosis. The patients diagnosed during the second trimester received six courses of neoadjuvant chemotherapy type FEC (5-fluorouracil, epirubicin, cyclophosphamide). Locoregional radiotherapy and surgery were postponed until after delivery. The three patients diagnosed during the third trimester received adequate therapy after delivery. The mean age of the patients at the time of diagnosis was 37 years (range: 33-40 years) and all patients were diagnosed at an advanced stage. All patients were alive and free of symptoms and signs at the time of writing. All infants are healthy and no congenital malformation or stillbirth was observed. In conclusion, late diagnosis and poor prognosis of PABC are common in literature. Treatment options seem to be reduced in pregnant women and mainly depend on the patient's condition as well as on the gestational age at presentation. In a multidisciplinary approach, an optimal therapy schedule should be assessed depending on these two conditions.