Ultrasonic methods are commonly used in structural investigation of historical buildings because they are easily applicable and produce rapid results. Information about strength of museums, mosques, and building structures can be obtained using ultrasonic waves. Turkey is located in a region where destructive earthquakes take place frequently. Buildings suffer significant damage from the earthquakes and deterioration over time. Therefore, the bearing systems of historical monuments should be investigated and protective measures, if necessary, should be taken. This study aims to analyze the marble columns of Hagia Sophia museum, built in the thirteenth and Gulbahar Hatun Mosque, built in the fifteenth century by using ultrasonic measurements and to compare with each other. These two buildings are among the most important historical structures in the Eastern Black Sea region of Turkey. Ultrasonic velocity distribution of marble columns was obtained from ultrasonic measurements with specific data acquisition. The velocity maps were analyzed and compared with both literature values and one another. The qualities of the main columns in the structures were determined through the use of some semi-quantitative calculations. The results show that the columns of Gulbahar Hatun Mosque were of low quality and that its columns had micro cracks. However, the columns of Hagia Sophia museum are in better condition.