This is the first checklist of Maine mosses since the publication of the state bryoflora, Maine Mosses. The checklist lists and ranks the 455 taxa of mosses that have been collected in Maine. This includes collections cited in Maine Mosses and/or the Tropicos Database of the Missouri Botanical Garden (denoted by M). These collections have been verified by Bruce Allen, Lewis Anderson, or Richard Andrus. Literature reports cited in Maine Mosses are denoted by m. Also included are collections in the database of the Consortium of North American Bryological Herbaria (denoted by r). The identity of these latter collections is mostly unverified with the exception of the Sphagnum. An * denotes species not yet found in Maine but expected to occur there.