Thirty independent clinical isolates of Staphylococcus lugdunensis were tested for expression of haemolysin characteristics of Staphylococcus aureus and for the presence of DNA sequences with homology to S. aureus toxin genes. Twenty-six strains produced a thermostable haemolysin with greatest activity against rabbit erythrocytes. DNA-DNA hybridisation was performed with S. lugdunesis DNA and probed with the alpha, beta, delta and gamma toxin gene probes of S. aureus as well as that for coagulase. Hybridisation was found with the delta probe in 28 strains including 6 which did not express haemolysin. Two strains did not hybridise with any of the probes. These findings suggest that S. lugdunensis strains produce a delta-like toxin which shares homology with the delta toxin of S. aureus.