Little is known about the diversity, distribution, and relative abundance of bats in northeastern Alberta, Canada. Between 1999 and 2007, we conducted summer bat surveys in the Athabasca and Cold Lake oil sands regions of northeastern Alberta, in response to increased industrial development and a need for greater understanding of species occurrences. We used mist nets (242 sites over 157 nights) and acoustic monitoring (920 sites over 126 nights) to determine the diversity and distribution of bats in the region. We captured 577 bats, representing 5 species, including: 260 Northern Myotis (Myotis septentrionalis); 193 Little Brown Myotis (M. lucifugus); 101 Silver-haired Bats (Lasionycteris noctivagans); 12 Hoary Bats (Lasiurus cinereus); and 11 Eastern Red Bats (L. borealis). Data from Anabat™ echolocation detectors indicated the highest activity for unclassified Myotis, Little Brown Myotis, Big Brown Bats (Eptesicus fuscus)/Silver-haired Bats, and Northern Myotis. Results suggest that the Northern Myotis may be more common in northeastern Alberta than previously thought. Based on the combined capture and echolocation data, Eastern Red Bats and Hoary Bats may be more common, or have increased ranges, than previously considered. Although expected to be relatively common, our failure to capture Big Brown Bats suggests that this species may be absent from the study area. Captures of adult males for all 3 migratory bat species (Eastern Red Bats, Hoary Bats, and Silver-haired Bats) represent the most northerly records in western Canada of adult males. This paper demonstrates the value in combining short-term, localized survey data such that more regional trends in the diversity, distribution, and relative abundance of bats can be better understood.