In this study, we successfully transferred the Escherichia coli beta-galactosidase gene. LacZ, into the chicken tendon and tendon sheath by a recombinant adenovirus. The recombinant adenovirus Adv-beta gal that carried the E. coli LacZ gene was constructed by homologous recombination in 293 cells (human transformed embryonic kidney) between the expressing vector and the ClaI large fragment of adenovirus 5 genome. Each chicken received a 10 microliters injection containing 10(5) plaque-forming units of recombinant virus Adv-beta gal. into the tendon sheath of the long toe Samples of tendon and tendon sheath were harvested at 3.30, and 75 days after the injection. The LacZ gene transfer was detected for its coding product beta-galactosidase by staining with X-gal solution. The results showed that all tendon and tendon sheath samples from the three harvest times stained positive (blue). The tendon sheath samples were more extensively stained; staining of the tendon was limited to the epitenon layer. These data suggest that a functional exogenous gene can potentially be transferred into the tendon and tendon sheath by similar techniques; such techniques may be used to improve healing and reduce adhesion formation.