Spondyloepiphyseal dysplasia tarda (SEDT) is an X-linked recessive osteochondrodysplasia characterized by disproportionately short stature and degenerative joint disease. The objective of this study was to describe a novel nonsense mutation in the sedlin gene (SEDL) causing severe SEDT in a large Chinese pedigree. The clinical features of all affected individuals and female carriers were presented. Four affected males of the family were diagnosed with SEDT according to their clinical and radiological features. Direct DNA sequencing of SEDL was performed.