'Opihi are the most prized intertidal resource harvested in Hawai'i due to their great cultural and economic value. There are three endemic species of 'opihi found in Hawai'i: black-foot 'opihi or makaiauli (Cellana exarata), yellow-foot 'opihi or 'ālinalina (C. sandwicensis ), and the largest species, giant 'opihi or kō'ele (C. talcosa). This study used social and natural science research methods to understand the cultural use and selected ecological characteristics of 'opihi populations at Kalaupapa National Historical Park on the island of Moloka'i. Anthropological research methods of participant observation and informal interviews were used to investigate fisher utilization of resources and assess fisher perception of the health of the fishery. From August 2008 through November 2010, 55 interviews or “talk story” sessions were conducted with 15 fishers and residents of Kalaupapa and “Topside” Moloka'i. Most fishers interviewed harvested 'opihi (87%) and all considered the resource as healthy. Quantitative 'opihi surveys were conducted before and during harvest season at eight sites over two years (2009–2010) within Kalaupapa National Historical Park. 'Opihi densities were significantly different among sites for all three species (p<0.001), apparently due to wave exposure and habitat type. 'Opihi had higher densities in boulder habitat than in lava bench for small size classes of makaiauli and for most size classes of ko'ele. Harvest effort did not have significant effects on densities of the three 'opihi species in 2009–2010. Concurrent fisheries harvest observations indicated that the insignificant harvest effect was due to relatively small fishing effort at Kalaupapa. These results are important for the sustainable management of these resources.