This ethnographic study investigated the mathematical disposition of engineers. Structural engineers in two firms were observed in everyday practice. Observation and interview data were analyzed to elucidate the role of mathematics in solving engineering problems and the engineers' perceptions of the status of mathematics relative to other resources and constraints. The phenomenon of "engineering judgment" was found to shape the role of mathematics in engineering work and render the engineers' mathematical disposition--of "skeptical reverence"--distinct from the disposition currently developed in schools.