The agglomerates cropped out in the region of Ankara are composed of tuffic intercalations and andesite blocks ranging from few centimeters to almost a meter. The presence of occasionally weathered material results in development of loose fabric. Preparation of suitable test specimens from these agglomerates is very difficult. In the present study, investigation of the relationships between uniaxial compressive strength and petrographical composition of the agglomerates was intended and the data obtained was analyzed using simple and multiple regression techniques. Generally, uniaxial compressive strength of the studied rock is controlled by the content of tuff if the tuff content in the specimen exceeds 20% of all constituents of the agglomerates. It is also noted that, the failure cracks generally propogate through the tuff indicating an intragranular failure. As a result, the uniaxial compressive strength of Ankara agglomerates can be practically predicted by using the petrographical composition-strength relationships that were investigated in this study.