The effects of flipper bands, implanted tags/gastric lavage and external instrument attachment on the performance of Adelie penguins were investigated over three seasons at Bechervaise Island, Mac. Robertson Land, Antarctica. The return rates of birds carrying bands and/or implanted electronic transponders were compared to investigate the contribution of bands to bird mortality and to determine rates of band and tag loss. There was a reduction in return rates of birds banded for more than one season, but no evidence of band or tag loss over a single winter. The attachment of satellite tracking devices during the incubation period or for several consecutive trips during chick rearing resulted in increased foraging trip durations and reduced breeding success. Attachment for a single foraging trip post-hatching caused no significant increase in foraging trip durations nor any detectable effect on water turnover rates. No reduction in fledging rates of chicks from nests of stomach lavaged birds was detected over two breeding seasons. The implications of these findings for the CCAMLR Ecosystem Monitoring Program are discussed.