Gul's visit comes weeks after Kosovo's independence, which Turkey recognized, but Romania did not.
Romania also supports the involvement of Gaz de France in the Nabucco project — the U.S- and European Union-backed pipeline that will reduce energy dependency on Russia by bringing gas from the Caspian Sea region through Turkey and Romania.
Ankara rejects the participation of French company in the pipeline construction.
Gul is joined by businessmen during his trip to Romania. In recent years, trade has increased between Romania and Turkey, now worth US$7 billion (euro4.6 billion).