Submitted in fulfillment of a 2009 Nantucket Biodiversity Initiative grant. We tested a Rapid Assessment Protocol for Spiders and Millipedes (RAPSM) in sandplain grassland and coastal heathland on Nantucket Island, Massachusetts. The objective of this protocol is to efficiently capture most of the available species within a defined area and provide species diversity datasets that are comparable between habitats. The RAPSM requires a combination of two person-hours of litter sorting and one person-hour of hand collecting (sweep-netting) in individual 100 m2 circular plots. We collected 538 spiders representing 36 species (188 were identifiable) from seven plots. The average number of spiders collected (adult and juvenile) per plot was 77 and the average number of species per plot was 12. On average, there are 0.77 spiders per square meter of sandplain grassland and coastal heathland within our study area. Litter sorting produced the most complete collection as indicated by accumulation curves. The RAPSM species list contains 71 percent of the species in a season adjusted species list for the study area and they are 58 percent similar. Our data suggest there is high beta diversity in the sandplain grassland and coastal heathland habitat. Millipedes will be sent to the Chicago Field Museum for identification.