Bone disease occurring in multiple myeloma is usually evaluated using radiological methods. These methods, however, provide not much information about the dynamic process of bone resorption and formation. This study analysed levels of serum markers of bone turnover (ICTP and OC), reflecting function of osteoclasts and osteoblasts. It demonstrates increased level of ICTP in 75 patients with MM compared to control group (8 persons) and patients with Waldenström's macroglobulinemia (10 persons). The level of ICTP was also higher in patients with more advanced bone disease and probably in higher stage of disease according to Salmon and Durie classification. This tendency was not observed in relation to OC. Result of the research confirms that ICTP may incur sensitive and specific markers of bone lesions in multiple myeloma.