diff --git a/doc/api/csp_buffer_h.rst b/doc/api/csp_buffer_h.rst
index 49d9b2b53..74cb87c8a 100644
--- a/doc/api/csp_buffer_h.rst
+++ b/doc/api/csp_buffer_h.rst
@@ -13,5 +13,4 @@ Interface Functions
 .. autocfunction:: csp_buffer.h::csp_buffer_clone
 .. autocfunction:: csp_buffer.h::csp_buffer_remaining
 .. autocfunction:: csp_buffer.h::csp_buffer_init
-.. autocfunction:: csp_buffer.h::csp_buffer_data_size
 .. autocfunction:: csp_buffer.h::csp_buffer_refc_inc
diff --git a/include/csp/csp_buffer.h b/include/csp/csp_buffer.h
index 2969bcd24..d9cce32ef 100644
--- a/include/csp/csp_buffer.h
+++ b/include/csp/csp_buffer.h
@@ -60,12 +60,6 @@ int csp_buffer_remaining(void);
 
 void csp_buffer_init(void);
 
-/**
- *
- * @return CSP buffer data size.
- */
-size_t csp_buffer_data_size(void);
-
 /**
  * Increase reference counter of buffer.
  * Use csp_buffer_free() to decrement