The initial results of the first formal survey of the bee fauna of Pennsylvania are reported. Specimens were examined from some 20 private, research and institutional collections in and around the state, as well as from pan-trapping and sweep-netting results from three years (2005–2007) of surveying by the Pennsylvania Department of Agriculture (PDA) Apiary Inspection Service. Of the 371 species reported here, 150 are new state records, including 27 of the 98 species found in the PDA surveys. Non-native species are indicated along with the earliest year of collection in the state and, for all species, the range of collection dates and the most recent year of collection are reported.