Toll-like receptor (TLR) 3 is a member of the TLR family that confers innate immunity by recognizing viral pathogens. Herein, we report that the TLR3 isoform is expressed on human primary cells and cell lines. This isoform has 2, 520 bp cDNAs compared to the 2, 712 bp of full cDNA, is produced by deletion of an intron-like sequence within exon 4 and is co-expressed with wild type TLR3 in primary human astrocytes and glioblastoma cell lines. This finding suggests the TLR3 isoform in astrocytes may have a different immunological role for binding ligands during the immune response in brain.