Many clinical CEST MRI methods have been developed and disseminated during the last few years, and the expansion of clinical CEST MRI will likely continue. A common phantom is needed to standardize the development and implementation of CEST methods. In this study, we have developed a clinical CEST MRI phantom with high-quality gelatin to test a range of concentrations, pH values, and T1 relaxation times. The experimental conditions of the CEST saturation and various post-saturation acquisition methods can be tested. This standard phantom can be used to support many applications within the CEST MRI research community.