Dysregulation of microRNA (miR) is often associated with cancer development and progression. Aberrant expression of miR-134 has been found in some types of cancer. However, its expression and function in osteosarcoma remain unclear. The aim of this study was to explore the effects of miR-134 in osteosarcoma tumorigenesis and development. The expression level of miR-134 was quantified by real-time reverse transcription-polymerase chain reaction in human osteosarcoma cell lines and tissues.