diff --git a/Doc/c-api/init.rst b/Doc/c-api/init.rst
index 2cdc0527dff..a88873bd8f2 100644
--- a/Doc/c-api/init.rst
+++ b/Doc/c-api/init.rst
@@ -1383,6 +1383,11 @@ These functions are only intended to be used by advanced debugging tools.
    Return the interpreter state object at the head of the list of all such objects.
 
 
+.. c:function:: PyInterpreterState* PyInterpreterState_Main()
+
+   Return the main interpreter state object.
+
+
 .. c:function:: PyInterpreterState* PyInterpreterState_Next(PyInterpreterState *interp)
 
    Return the next interpreter state object after *interp* from the list of all
diff --git a/Misc/NEWS.d/next/Documentation/2019-03-08-15-39-47.bpo-36157.nF1pP1.rst b/Misc/NEWS.d/next/Documentation/2019-03-08-15-39-47.bpo-36157.nF1pP1.rst
new file mode 100644
index 00000000000..ff0293e8407
--- /dev/null
+++ b/Misc/NEWS.d/next/Documentation/2019-03-08-15-39-47.bpo-36157.nF1pP1.rst
@@ -0,0 +1 @@
+Added Documention for  PyInterpreterState_Main().
\ No newline at end of file