The Kasimovian is the third stage in the Pennsylvanian, the youngest subsystem of the Carboniferous. It is preceded by the Moscovian and is followed by the Gzhelian. This stage approximately correlates with American Missourian stage, European Stephanian stage and lower part of Xiaodushanian stage in Chinese stratigraphy.  

Although the working group of the SCCS, responsible for defining the GSSP close to the base of the Kasimovian, has been active for nearly 20 years, no decision regarding the definition of this boundary has been forthcoming and no GSSP had been assigned yet.