Multiple studies have shown that HOX antisense intergenic RNA (HOTAIR), an oncogenic long non‑coding RNA (lncRNA), is dysregulated in leukemia and is involved in tumor progression. The aim of the present study was to determine whether HOTAIR could serve as a novel biomarker for the diagnosis of multiple myeloma (MM), and to investigate its role in regards to MM cell viability and chemoresistance to dexamethasone (DEX). The results revealed that the expression of HOTAIR was significantly upregulated in serum, bone marrow and primary CD138+ cells from MM patients compared with those from normal controls as determined by qPCR. HOTAIR expression was obviously increased in MM cell lines compared to that in normal plasma cells. ROC curve analysis showed that the serum level of HOTAIR exhibited a higher diagnostic value for MM. Furthermore, loss‑of‑functional assays indicated that HOTAIR inhibition suppressed MM cell viability by arresting the cell cycle at the G0/G1 phase as determined by cell viability assay and flow cytometry. An in‑depth study revealed that knockdown of HOTAIR led to decreased chemoresistance of DEX in MM cells by regulating the JAK2/STAT3 signaling pathway. Taken together, our findings suggest that upregulation of serum HOTAIR may prove to be a novel biomarker for the diagnosis of MM. HOTAIR promoted MM cell viability and increased chemoresistance of MM to DEX via the JAK2/STAT3 signaling pathway, indicating HOTAIR may also serve as a potential therapeutic target for MM.