The occurrence of B-cell chronic lymphocytic leukemia (B-CLL) and another B-cell neoplasm in the same patient is a rare event and is mostly described in the literature as single case reports. In most cases reported in the literature, CLL was diagnosed several years before multiple myeloma. Some patients were only observed for CLL without therapy, whereas others had already been treated for CLL when the diagnosis of myeloma was established. Some authors came to a conclusion that therapy used for treating CLL can induce some secondary neoplasms, like multiple myeloma. We present a male patient who was diagnosed with multiple myeloma 11 years after B-CLL had been diagnosed. Two hematologic neoplasms in one patient could be a diagnostic problem, but also a therapeutic challenge.