diff --git a/lib/plsql/jdbc_connection.rb b/lib/plsql/jdbc_connection.rb
index 1b930d98..5c5674ce 100644
--- a/lib/plsql/jdbc_connection.rb
+++ b/lib/plsql/jdbc_connection.rb
@@ -107,7 +107,7 @@ def bind_param(arg, value, metadata)
         if metadata[:in_out] =~ /OUT/
           @out_types[arg] = type || ora_value.class
           @out_index[arg] = bind_param_index(arg)
-          if ['TABLE','VARRAY','OBJECT'].include?(metadata[:data_type])
+          if ['TABLE','VARRAY','OBJECT','XMLTYPE'].include?(metadata[:data_type])
             @statement.registerOutParameter(@out_index[arg], @connection.get_java_sql_type(ora_value,type),
               metadata[:sql_type_name])
           else
@@ -277,7 +277,7 @@ def set_bind_variable(stmt, i, value, type=nil, length=nil, metadata={})
       when :Time, :'Java::JavaSql::Timestamp'
         stmt.send("setTimestamp#{key && "AtName"}", key || i, value)
       when :NilClass
-        if ['TABLE', 'VARRAY', 'OBJECT'].include?(metadata[:data_type])
+        if ['TABLE', 'VARRAY', 'OBJECT','XMLTYPE'].include?(metadata[:data_type])
           stmt.send("setNull#{key && "AtName"}", key || i, get_java_sql_type(value, type),
             metadata[:sql_type_name])
         elsif metadata[:data_type] == 'REF CURSOR'
diff --git a/lib/plsql/oci_connection.rb b/lib/plsql/oci_connection.rb
index 374023d9..e9e3c310 100644
--- a/lib/plsql/oci_connection.rb
+++ b/lib/plsql/oci_connection.rb
@@ -159,7 +159,7 @@ def plsql_to_ruby_data_type(metadata)
         [DateTime, nil]
       when "TIMESTAMP", "TIMESTAMP WITH TIME ZONE", "TIMESTAMP WITH LOCAL TIME ZONE"
         [Time, nil]
-      when "TABLE", "VARRAY", "OBJECT"
+      when "TABLE", "VARRAY", "OBJECT", "XMLTYPE"
         # create Ruby class for collection
         klass = OCI8::Object::Base.get_class_by_typename(metadata[:sql_type_name])
         unless klass
diff --git a/lib/plsql/procedure.rb b/lib/plsql/procedure.rb
index 4ad3ff17..f17be90a 100644
--- a/lib/plsql/procedure.rb
+++ b/lib/plsql/procedure.rb
@@ -75,7 +75,7 @@ def self.type_to_sql(metadata) #:nodoc:
       when 'NVARCHAR2', 'NCHAR'
         length = metadata[:char_length]
         "#{metadata[:data_type]}#{length && "(#{length})"}"
-      when 'PL/SQL TABLE', 'TABLE', 'VARRAY', 'OBJECT'
+      when 'PL/SQL TABLE', 'TABLE', 'VARRAY', 'OBJECT', 'XMLTYPE'
         metadata[:sql_type_name]
       else
         metadata[:data_type]
diff --git a/lib/plsql/procedure_call.rb b/lib/plsql/procedure_call.rb
index 74c95c9e..5955fb83 100644
--- a/lib/plsql/procedure_call.rb
+++ b/lib/plsql/procedure_call.rb
@@ -111,7 +111,7 @@ def get_overload_from_arguments_list(args)
     MATCHING_TYPES = {
       :integer => ['NUMBER', 'NATURAL', 'NATURALN', 'POSITIVE', 'POSITIVEN', 'SIGNTYPE', 'SIMPLE_INTEGER', 'PLS_INTEGER', 'BINARY_INTEGER'],
       :decimal => ['NUMBER', 'BINARY_FLOAT', 'BINARY_DOUBLE'],
-      :string => ['VARCHAR', 'VARCHAR2', 'NVARCHAR2', 'CHAR', 'NCHAR', 'CLOB', 'BLOB'],
+      :string => ['VARCHAR', 'VARCHAR2', 'NVARCHAR2', 'CHAR', 'NCHAR', 'CLOB', 'BLOB', 'XMLTYPE'],
       :date => ['DATE'],
       :time => ['DATE', 'TIMESTAMP', 'TIMESTAMP WITH TIME ZONE', 'TIMESTAMP WITH LOCAL TIME ZONE'],
       :boolean => ['PL/SQL BOOLEAN'],
@@ -236,6 +236,14 @@ def add_argument(argument, value, argument_metadata=nil)
         @bind_values[argument] = value.nil? ? nil : (value ? 1 : 0)
         @bind_metadata[argument] = argument_metadata.merge(:data_type => "NUMBER", :data_precision => 1)
         "l_#{argument}"
+      when 'UNDEFINED'
+        if argument_metadata[:type_name] == 'XMLTYPE'
+          @declare_sql << "l_#{argument} XMLTYPE;\n"
+          @assignment_sql << "l_#{argument} := XMLTYPE(:#{argument});\n" if not value.nil?
+          @bind_values[argument] = value if not value.nil?
+          @bind_metadata[argument] = argument_metadata.merge(:data_type => "CLOB")
+          "l_#{argument}"
+        end
       else
         # TABLE or PL/SQL TABLE type defined inside package
         if argument_metadata[:tmp_table_name]
@@ -383,6 +391,15 @@ def add_return_variable(argument, argument_metadata, is_return_value=false)
           end
         end
         "l_#{argument} := " if is_return_value
+      when 'UNDEFINED'
+        if argument_metadata[:type_name] == 'XMLTYPE'
+          @declare_sql << "l_#{argument} XMLTYPE;\n" if is_return_value
+          bind_variable = :"o_#{argument}"
+          @return_vars << bind_variable
+          @return_vars_metadata[bind_variable] = argument_metadata.merge(:data_type => "CLOB")
+          @return_sql << ":#{bind_variable} := CASE WHEN l_#{argument} IS NOT NULL THEN l_#{argument}.getclobval() END;\n"
+          "l_#{argument} := " if is_return_value
+        end
       when 'PL/SQL BOOLEAN'
         @declare_sql << "l_#{argument} BOOLEAN;\n" if is_return_value
         @declare_sql << "o_#{argument} NUMBER(1);\n"
@@ -496,6 +513,10 @@ def return_variable_value(argument, argument_metadata)
       when 'PL/SQL BOOLEAN'
         numeric_value = @cursor[":o_#{argument}"]
         numeric_value.nil? ? nil : numeric_value == 1
+      when 'UNDEFINED'
+        if argument_metadata[:type_name] == 'XMLTYPE'
+          @cursor[":o_#{argument}"]
+        end
       else
         if argument_metadata[:tmp_table_name]
           is_index_by_table = argument_metadata[:data_type] == 'PL/SQL TABLE'
diff --git a/lib/plsql/variable.rb b/lib/plsql/variable.rb
index d5243dab..667fc513 100644
--- a/lib/plsql/variable.rb
+++ b/lib/plsql/variable.rb
@@ -51,7 +51,8 @@ def metadata(type_string)
         {:data_type => $1, :data_length => $3.to_i, :in_out => 'IN/OUT'}
       when /^(CLOB|NCLOB|BLOB)$/,
           /^(NUMBER)(\(.*\))?$/, /^(NATURAL|NATURALN|POSITIVE|POSITIVEN|SIGNTYPE|SIMPLE_INTEGER|PLS_INTEGER|BINARY_INTEGER)$/,
-          /^(DATE|TIMESTAMP|TIMESTAMP WITH TIME ZONE|TIMESTAMP WITH LOCAL TIME ZONE)$/
+          /^(DATE|TIMESTAMP|TIMESTAMP WITH TIME ZONE|TIMESTAMP WITH LOCAL TIME ZONE)$/,
+          /^(XMLTYPE)$/
         {:data_type => $1, :in_out => 'IN/OUT'}
       when /^INTEGER$/
         {:data_type => 'NUMBER', :in_out => 'IN/OUT'}
@@ -143,4 +144,4 @@ def call_sql(params_string)
 
   end
 
-end
\ No newline at end of file
+end
diff --git a/spec/plsql/procedure_spec.rb b/spec/plsql/procedure_spec.rb
index 4bdee21a..12c8c1e3 100644
--- a/spec/plsql/procedure_spec.rb
+++ b/spec/plsql/procedure_spec.rb
@@ -235,6 +235,53 @@
 
   end
 
+  describe "Function or procedure with XMLType parameters" do
+    before(:all) do
+      plsql.connect! CONNECTION_PARAMS
+      plsql.execute <<-SQL
+        CREATE OR REPLACE FUNCTION test_xmltype
+          ( p_xml XMLTYPE )
+          RETURN XMLTYPE
+        IS
+        BEGIN
+          RETURN p_xml;
+        END test_xmltype;
+      SQL
+      plsql.execute <<-SQL
+        CREATE OR REPLACE PROCEDURE test_xmltype2
+          ( p_xml XMLTYPE, po_xml OUT XMLTYPE )
+        IS
+        BEGIN
+          po_xml := p_xml;
+        END test_xmltype2;
+      SQL
+    end
+
+    after(:all) do
+      plsql.execute "DROP FUNCTION test_xmltype"
+      plsql.execute "DROP PROCEDURE test_xmltype2"
+      plsql.logoff
+    end
+
+    it "should process XMLType parameters" do
+      xml = '<DUMMY>value</DUMMY>'
+      result = plsql.test_xmltype(xml)
+      expect(result).to eq('<DUMMY>value</DUMMY>')
+    end
+
+    it "should work when passing a NULL value" do
+      result = plsql.test_xmltype(nil)
+      expect(result).to be_nil
+    end
+
+    it "should assign input parameter to putput parameter" do
+      xml = '<DUMMY>value</DUMMY>'
+      result = plsql.test_xmltype2(xml)
+      expect(result[:po_xml]).to eq('<DUMMY>value</DUMMY>')
+    end
+  end
+
+
   describe "Procedure with output parameters" do
     before(:all) do
       plsql.connect! CONNECTION_PARAMS