In this paper * n will present the result of a study conceming the customs of Erzurum in the 18 th century, which is based upon the mukataa and gümrük registers. The mukataa registers form a consecutive series beginning w ith the da w n of the 18 th century ı unfortunately the customs registers have survided only for certain years ı As Erzurum often has been the theatre of war, nothing remains of the local kadı registers, which normally would have permitted us to answer questions which the mukataa and gümrük do'cuments leave unanswered. Apart from quantitative data the two extant series contain information on the manner in which the customs of Erzurum were administered; thus our study, while mainly economic, also is relevent to political historians.