Resumo. The economic importance of some species of Anastrepha Schiner, 1868 (Diptera, Tephritidae) has contributed to expanding knowledge of fruit fly diversity in Brazil, due to the numerous surveys conducted in the country since the late 1970s. However, a new record of Anastrepha may sometimes be revealed by an entomologist traveling through a bucolic landscape. In this case, a fly entered through the window of a vehicle traveling along a dirt road in the municipality of Cáceres, in the state of Mato Grosso (MT), and landed on the windshield. The yellow coloration of the accidental passenger caught the attention of the traveling entomologist, who collected it in a small plastic vial and later took it to the Laboratory of Insect Taxonomy (LTI) of "Luiz de Queiroz" College of Agriculture (ESALQ/USP), Piracicaba, state of São Paulo, for identification. This unusual collection represents the first record of Anastrepha flavipennis Greene, 1934 in MT. Although A. flavipennis has been recorded in eight Brazilian states, including now MT, few specimens have generally been collected in surveys, and only a single host is known. In addition to the morphological characters used to identify A. flavipennis, an identification key to the 27 Anastrepha species known from MT was prepared.