In the present invention there is provided a pharmaceutical composition for oral administration which comprises bendamustine or a pharmaceutically acceptable, ester, salt or solvate thereof as an active ingredient, and a pharmaceutically acceptable excipient and which shows a dissolution of the bendamustine of at least 60% in 20 minutes, 70% in 40 minutes and 80% in 60 minutes, as measured with a paddle apparatus at 50 rpm according to the European Pharmacopoeia in 500 ml of a dissolution medium at a pH of 1.5. The invention further relates to the above pharmaceutical composition for use for the oral treatment of a medical condition which is selected from chronic lymphocytic leukemia, acute lymphocytic leukaemia, chronic myelocytic leukaemia, acute myelocytic leukaemia, Hodgkin's disease, non-Hodgkin's lymphoma, multiple myeloma, breast cancer, ovarian cancer, small cell lung cancer and non-small cell lung cancer.