diff --git a/include/cantera/base/stringUtils.h b/include/cantera/base/stringUtils.h
index 363897374..b0bb79e37 100644
--- a/include/cantera/base/stringUtils.h
+++ b/include/cantera/base/stringUtils.h
@@ -101,6 +101,7 @@ compositionMap parseCompString(const std::string& ss,
  *              pairs on multiple lines
  *  @param w    Output vector consisting of single key:composition
  *              items in each index.
+ *  @deprecated Unused. To be removed after Cantera 2.2.
  */
 void split(const std::string& ss, std::vector<std::string>& w);
 
@@ -111,6 +112,7 @@ void split(const std::string& ss, std::vector<std::string>& w);
  *   @param a       Output pointer to a vector of floats
  *   @param delim   character delimiter. Defaults to a space
  *   @return        Returns the number of floats found and converted
+ *  @deprecated Unused. To be removed after Cantera 2.2.
  */
 int fillArrayFromString(const std::string& str, doublereal* const a,
                         const char delim = ' ');
diff --git a/src/base/stringUtils.cpp b/src/base/stringUtils.cpp
index 82cebb197..ef340d3c6 100644
--- a/src/base/stringUtils.cpp
+++ b/src/base/stringUtils.cpp
@@ -166,6 +166,7 @@ compositionMap parseCompString(const std::string& ss,
 
 void split(const std::string& ss, std::vector<std::string>& w)
 {
+    warn_deprecated("split", "To be removed after Cantera 2.2.");
     std::string s = ss;
     std::string::size_type ibegin, iend;
     std::string name, num, nm;
@@ -188,6 +189,7 @@ void split(const std::string& ss, std::vector<std::string>& w)
 int fillArrayFromString(const std::string& str,
                         doublereal* const a, const char delim)
 {
+    warn_deprecated("fillArrayFromString", "To be removed after Cantera 2.2.");
     std::string::size_type iloc;
     int count = 0;
     std::string num;