For three austral spring and summer field seasons, 1994-97, the Antarctic Site Inventory project has collected data and information about Antarctic Peninsula visitor sites. These data and information are intended to assist in establishing baselines for: future environmental assessments under the soon-to-be-effective Antarctic Environmental Protocol; designing future monitoring programmes to detect changes in fauna, flora, and other major features at these sites; and how best to minimize potential adverse impacts of human visitor activity. CEMP Standard Methods were relied upon in establishing the project's methodology, particularly with respect to counting penguin nests and chicks. At each site, investigators attempt to select and establish prospective control (seldom disturbed) colonies and experimental (frequently disturbed) colonies to census. The intent is to repeat censuses regularly both near and far from landing beaches where visitors access a site, allowing comparisons over time between areas that have much human activity and those without such activity. A power analysis indicates the Inventory's methodology fully conforms with sampling strategies recommended by the CEMP working Group, enabling the Inventory to detect a 10% or 20% change in a parameter with a significance level as. 01 and a statistical power P (= 1-ß) ≥ 0.8.