It is well demonstrated that various peptides derived from elastin are biologically active. The hexapeptide (Val-Gly-Val-Ala-Pro-Gly; VI) as well as elastin peptides were demonstrated to be chemotactic for fibroblasts, while kappa-elastin had marked biological effects on human PMNLs. The aim of our present work was to synthesize various elastin peptides and compare their action to that of kappa-elastin and this hexapeptide. The results indicate that the hexapeptide (Val-Gly-Val-Ala-Pro-Gly) and the two other synthesized hexapeptides (Pro-Gly-Val-Gly-Val-Ala; III and Val-Gly-Val-Gly-Val-Ala; IV) had very similar and specific effects on intracellular free calcium metabolism, on superoxide anion production and elastase release. The other peptides had no effects on these parameters, except a tripeptide (Val-Gly-Val; V) on superoxide anion production. Moreover, the effect of the hexapeptides (III and VI) could be abolished by Pertussis toxin preincubation. All peptides had very similar stimulating effects on H2O2 production and myeloperoxidase release. We conclude that most probably the peptide size and conformation, as well as peptide composition play a role in the biological effects of these peptides, through specific receptors on PMNLs surface.