Recently, the Optimal Spectral Sampling (OSS) method was implemented in a development version of the Community Radiative Transfer Model (CRTM) at JCSDA. This presentation describes the way that the OSS is implemented in CRTM, and some preliminary evaluation of the performance of the CRTM-OSS in comparison with CRTM-ODPS method. One of the important benefits of the OSS method is its capability to simulate unapodized radiance, which could lead to better sensitivity in retrievals and data assimilation for numerical weather prediction (NWP). The accuracy and speed of the OSS simulations are two trade-off factors, depending on how many spectral nodes are used during training and simulation. In general, the OSS simulations of hyper spectral IR sensors, such as IASI and CrIS, can archive similar accuracy and double speed as compared to the CRTM-ODPS simulations.