Bovine fetal ligamentum nuchae fibroblasts were cultured on tissue culture plastic or directly on killed fetal ligament tissue. Soluble elastin production and formation of insoluble elastin where monitored by radioimmunoassay and incorporation of [14C] lysine into desmosine, respectively. Cells grown on tissue culture plastic synthesized elastin precursors but were unable to form insoluble elastin whereas cells grown on dead ligament not only formed insoluble elastin, but showed an increase in levels of immunoreactive soluble elastin in culture medium. Stimulation of elastin synthesis by a soluble factor originating in ligament tissue is unlikely since medium conditioned by viable or nonviable ligament tissue had no effect on ligament cells cultured on plastic. Thus, direct cell-matrix contact appears to be important in mediating elastin biosynthesis.