As a result of the present investigations 18 species of flat bark beetles are known to occur in Atlantic Canada, 10 in New Brunswick, 17 in Nova Scotia, four on Prince Edward Island, six on insular Newfoundland, and one in Labrador. Twenty-three new provincial records are reported and nine species, Uleiota debilis (LeConte), Uleiota dubius (Fabricius), Nausibius clavicornis (Kugelann), Ahasverus advena (Waltl), Cryptolestes pusillus (Schönherr), Cryptolestes turcicus (Grouvelle), Charaphloeus convexulus (LeConte), Charaphloeus species nr. adustus, and Placonotus zimmermanni (LeConte) are newly recorded in the region, one of which C. sp. nr. adustus, is newly recorded in Canada as a whole. Eight species are cosmopolitan species introduced to the region and North America, nine are native Nearctic species, and one, Pediacus fuscus Erichson, is Holarctic in distribution. All the introduced species except for one (Silvanus bidentatus (Fabricius), a saproxylic species) are found on various stored products, whereas all the native species are saproxylic. Ahasverus longulus (Blatchley), is removed from the species list of New Brunswick and Charophloeus adustus (LeConte) is removed from the species list of Nova Scotia. One tropical Asian species, Cryptamorpha desjardinsi (Guérin-Méneville), has been intercepted in the region in imported produce, but is not established. The substantial proportion (44%) of the fauna that is comprised of introduced species is highlighted, almost all of which are synanthropic species associated with various dried stored products. The island faunas of Prince Edward Island, Cape Breton Island, and insular Newfoundland are diminished in comparison to the mainland fauna, that of Prince Edward Island being exceptionally so in comparison to other saproxylic groups found there. Of the ten native species, four can be categorized as 'apparently rare' (i.e., comprising ≤ 0.005% of specimens examined from the region). It is possibly that the apparent scarcity of these species is related to the long history of forest management in Atlantic Canada. Further research on saproxylic faunas in the region is urged to help determine the impact that forest practices may have had on them and to seek measures which might lessen or ameliorate such impacts.