The goal of the study was to investigate the levels of interleukin-27 (IL-27) and IL-17 in bone marrow (BM) and peripheral blood (PB) of multiple myeloma (MM). The levels of IL-27 and IL-17 were determined in MM patients and controls using ELISA. The results showed a decreased IL-27 and elevated IL-17 level in MM patients and a negative association of IL-27 with IL-17. The ratio of IL-27:IL-17 in BM of newly diagnosed MM was significantly decreased and correlated with the progression of disease. Multivariate analysis showed that a higher ratio of IL-27:IL-17 in BM was associated with a superior progression-free survival (HR = 0.160; 95% CI: 0.058–0.443; p < 0.001). Our results suggest that there might be a possible competitive role of IL-27 and IL-17 in MM.