Anisotropic rocks are those whose mechanical properties vary with direction. Rock anisotropy can become significant factors in various rock engineering applications such as in situ stress estimation applying overcoring method and wellbore stability investigation. Among several types of anisotropy, transversely isotropy is widely considered to characterize elastic constants of anisotropic rocks such as gneiss, schist, and shale. Several methods have been proposed to characterize these elastic constants, using (1) uniaxial compression tests with multiple cylindrical cores, (2) triaxial compression tests with single cylindrical core, (3) diametral loading tests with two cylindrical cores, (4) uniaxial compression, radial compression, and torsion tests with single hollow cylindrical core, and (5) a strip load test with single cylindrical core. In this study, over two hundred datasets of elastic constants for anisotropic rocks have been compiled based on these testing methods. These data sets have been collected and analyzed to investigate (1) the range of elastic constants, (2) the range of anisotropy ratio, (3) the validity of Saint-Venant empirical relation, and (4) the variation of apparent Young’s modulus with direction. The analysis reveals that (1) elastic constants and anisotropy ratio of anisotropic rocks exhibit wide distributions, (2) Saint-Venant empirical relation has to be carefully used, and (3) the trend of apparent Young’s modulus varies depending on the types of rocks.