Blocks of expanded polystyrene (EPS) were placed in a variety of habitats to investigate theirpotential as an egg-collection device for container-dwelling Aedes and Ochlerotatus species. Eggs from Ochlerotatusjaponicus, Oc. triseriatus, Oc. hendersoni, and Aedes albopictus were collected with EPS floats. The floatprovides an inexpensive, low-maintenance alternative to the Centers for Disease Control ovitrap for samplingcontainer-dwelling mosquito species that are important vectors of disease. Eggs collected on the floats havemany potential applications, including use in routine population surveillance; detection of Oc. japonicus, Ae.albopictus, and other container-dwelling species in new areas; species distribution studies; natural transovarialtransmission studies; ovipositional studies; collection of local field populations for insecticide resistance assays;assessment of adulticiding efficacy; and establishment of new laboratory colonies.