Abstract: The mechanical properties of five different rock types from south-eastern Nigeria were determined through uniaxial compressive strength (UCS) test, point load strength test, impact strength index test and natural density test. The results were correlated by using correlation coefficient and regression analyses. The equation of the best-fit line, and the correlation coefficient were determined for each regression. Among the four rock properties correlated in terms of drillability (penetration rate) of percussive or rotary drilling rig, the uniaxial compressive strength, the impact strength index and natural density are found to be the dominant properties affecting penetration rate of rotary drills.