To date, three closely-related TGFβ genes have been found in the mouse; TGFβ1, TGFβ2 and TGFβ3. Previous experiments have indicated that TGFβ1 and TGFβ2 may play important roles during mouse embryo-genesis. The present study now reports the distribution of transcripts of TGFβ3 in comparison to the other two genes and reveals overlapping but distinct patterns of RNA expression. TGFβ3 RNA is expressed in a diverse array of tissues including perichondrium, bone, intervertebral discs, mesenteries, pleura, heart, lung, palate, and amnion, as well as in central nervous system (CNS) structures such as the meninges, choroid plexus and the olfactory bulbs. Furthermore, in several organ systems, TGFβ3 transcripts are expressed during periods of active morphogenesis suggesting that the protein may be an important factor for the growth and differentiation of many embryonic tissues.