The promoter region of the human (h) thyroid hormone receptor (TR) β1 gene was isolated from a human placenta genomic library. Primer extension and S1 nuclease mapping confirmed a single transcriptional start site. DNA sequence analysis of the 5′ upstream region revealed the existence of a putative thyroid response element (TRE) which is highly homologous to TREs found in several thyroid hormone responsive genes. Binding of hTR protein to the promoter region of the hTRβ1 gene was confirmed by gel mobility shift assay. A transient transfection study demonstrated that hTR activated the expression of a reporter gene containing the promoter sequence of the hTRβ1 gene in a hormone dependent manner. The TRE in the hTRβ1 gene promoter may be involved in the autoregulation of hTRβ1 gene expression.