An　increasing　number　of　studies　have　demonstrated　that　microRNAs　participate　in　the　development　of　osteosarcoma　by　acting　as　tumour　suppressor　or　tumour-promoting　genes.　We　investigated　the　role　of　miR-504　in　the　growth　and　metastasis　of　osteosarcoma.　The　expression　of　miR-504　in　clinical　osteosarcoma　samples　was　higher　than　that　in　the　adjacent　normal　tissue　and　correlated　with　tumour　size　and　clinical　stage.　Tumour　protein　p53-inducible　nuclear　protein　1　(TP53INP1)　was　downregulated　in　the　clinical　osteosarcoma　samples　compared　with　the　adjacent　normal　tissues　and　was　consistently　correlated　with　the　clinical　stage.　The　results　of　dual-luciferase　reporter　assay　and　western　blot　analysis　demonstrated　that　the　TP53INP1　gene　is　a　direct　target　of　miR-504.　Altogether,　the　Cell　Counting　Kit-8　(CCK-8),　the　colony　formation,　the　flow　cytometry　and　the　Transwell　assay　results　demonstrated　that　miR-504　promoted　osteosarcoma　cell　growth　and　metastasis　in　vitro.　P73,　P21,　Bax,　cleaved-caspase-3　and　secreted　protein　acidic　and　rich　in　cysteine　(SPARC)　were　associated　with　the　suppressive　role　of　miR-504/TP53INP1.　The　overexpression　of　miR-504　in　osteosarcoma　xenografts　enhanced　the　tumour　growth　and　increased　the　metastatic　burden.　Collectively,　these　results　revealed　that　TP53INP1　is　a　target　gene　of　miR-504　and　that　miR-504　enhances　osteosarcoma　growth　and　promotes　distant　metastases　by　targeting　TP53INP1.　Thus,　miR-504/TP53INP1　may　be　associated　with　osteosarcoma　size　and　clinical　stage.