We report four patients with rheumatic disease (RD) and chronic myelogenous leukemia (CML). In two patients with Behcet's disease (BD) and rheumatoid arthritis (RA), CML developed after RD, in two patients with diffuse cutaneous systemic sclerosis and spondyloarthropathy, RD was diagnosed after CML. A variety of interactions have been described between hematological malignancies and RD. Nevertheless, few cases of RD have been documented associated with CML. It is unclear whether the development of CML in patients with RD and RD development after CML occurs by chance alone, is due to the underlying disease, or is facilitated by drugs. Whatever the cause is, it should be kept in mind that CML may develop in the course of RD and RD may be seen in CML patients.