The nesting behavior of Trachypus petiolatus is described from central Panamá. Females nested within aggregations in bare soil; they re-used nests from a prior generation, and provisioned their nests with small bees, mainly Apidae and Halictidae. These nests had a communal social organization among resident females, and also included one or more males. At least some males left the nest in the morning on a daily basis, and then returned later in the day. Based on limited nest excavations, we did not observe any parasitized cells, which may be associated with communal nesting.