The unconventional resource has become an interesting field of study and some source rocks have turned to be excellent reservoirs for generation and accumulation. Twenty- five percent of sedimentary rocks from Peninsular Malaysia are Paleozoic shales. The goal of this paper is to evaluate and characterize the shales in the Kroh Formation, which is one of the Western Belt formations in Peninsular Malaysia. Representative shale samples have been taken from different outcrops of the Kroh Formation, were performed to study the mineralogical and geochemical characteristics to determine the quantity of the organic matter and the minerals. The TOC values range from 2.02 to 7.01 wt and this range indicate that the shales have a very good source generative potential. These values fulfill the basic prerequisites of successful shale gas exploration. Results of X-ray Diffraction (XRD) indicate that the shale samples are mainly comprised of kaolinite as clay minerals and quartz and pyrite as non-clay minerals. In addition to illite, kaolinite, and quartz, Pyrite, calcite, and dolomite were identified within the shales through XRD. FTIR technique confirms the minerals that are present in the XRD. Knowing the clay minerals composition of the shale can be useful in planning for drilling and hydraulic fracturing of the Kroh Formation or similar characteristics. © 2019 The Authors.