In this study, we observed that (1) glucosamine sulfate inhibits MMP gene and protein expressions in MG-63 and SaOS-2 osteosarcoma cell lines, (2) glucosamine sulfate suppresses basal MMP expression in osteosarcoma cells, and (3) glucosamine sulfate most significantly affects MMP-3 expression compared to MMP-9 and MMP-2. This evidence concerns the gene MMP9 and osteosarcoma.