The 12 years Adam Smith spent as a commissioner of Scottish customs (1778-90) have been examined only in the most cursory fashion by scholars. Smith's appointment has usually been dismissed as a mere sinecure based on patronage. We believe that Smith's period of service as customs commissioner deserves a closer look. To this end we have examined a previously overlooked body of empirical evidence: the minutes and correspondence of the Scottish Customs Commission for the period of Smith's service. We use this record to evaluate his commission work in detail and also in relation to the doctrines in the Wealth of Nations.