Bentgrasses (Agrostis spp.) are extensively used on golf courses in temperate regions for putting greens, tees, and fairways. The three most commonly used bentgrasses, creeping bentgrass (Agrostis stolonifera L.), colonial bentgrass (Agrostis capillaris L.), and velvet bentgrass (Agrostis canina L.), are often difficult to identify on the basis of morphological features. As such, naturalized bentgrass clones collected from old turfs can be difficult to classify. The objective of this study was to determine if random amplified polymorphic DNA (RAPD) markers could identify 319 bentgrass clones according to species, ultimately to identify desirable velvet bentgrass germplasm for breeding projects. Germplasm sources included known velvet, creeping, and colonial bentgrasses, a seed collection of putative velvet bentgrass from the Azores, Portugal, and a clonal collection of putative velvet bentgrass from old Milwaukee golf courses. Five RAPD primers produced 82 polymorphic bands. Analysis of molecular variance (AMOVA) was used to partition variation among groups (14.7%), among populations within groups (16.2%), and among individuals within populations (69.1 %). A multidimensional scaling procedure (MDS) differentiated groups according to known species and allocated unknown plants into known clusters. The Milwaukee group was closely associated with creeping bentgrass cultivars while the Azores group associated with velvet bentgrass and colonial bentgrass. Flow cytometry confirmed ploidy levels of known and unknown clones. The clear differentiation between species suggests that RAPD markers are a useful tool for identifying bentgrass species.