diff -r 71a1f53c8203 -r 0eb420ce6567 Lib/test/test_csv.py
--- a/Lib/test/test_csv.py	Wed Jul 06 07:31:38 2011 +0200
+++ b/Lib/test/test_csv.py	Wed Jul 06 23:02:13 2011 +0200
@@ -124,6 +124,12 @@
             self.assertEqual(fileobj.read(),
                              expect + writer.dialect.lineterminator)
 
+    def _write_test_vary_doublequote(self, fields, expect, **kwargs):
+        kwargs.update(doublequote=True)
+        self._write_test(fields, expect, **kwargs)
+        kwargs.update(doublequote=False)
+        self._write_test(fields, expect, **kwargs)
+
     def test_write_arg_valid(self):
         self.assertRaises(csv.Error, self._write_test, None, '')
         self._write_test((), '')
@@ -183,6 +189,48 @@
         self._write_test(['a',1,'p,q'], 'a,1,p\\,q',
                          escapechar='\\', quoting = csv.QUOTE_NONE)
 
+    def test_write_escape_escapechar(self):
+        dialect_qminimal = dict(escapechar = '/',
+                                quoting = csv.QUOTE_MINIMAL)
+
+        dialect_qnone = dict(escapechar = '/',
+                             quoting = csv.QUOTE_NONE)
+
+        dialect_qall = dict(escapechar = '/',
+                            quoting = csv.QUOTE_ALL)
+
+        fields = ['a/',1]
+        self._write_test_vary_doublequote(fields, '"a//",1',
+                         **dialect_qminimal)
+        self._write_test_vary_doublequote(fields, 'a//,1',
+                         **dialect_qnone)
+        self._write_test_vary_doublequote(fields, '"a//","1"',
+                         **dialect_qall)
+
+        fields = ['a/b',1]
+        self._write_test_vary_doublequote(fields, '"a//b",1',
+                         **dialect_qminimal)
+        self._write_test_vary_doublequote(fields, 'a//b,1',
+                         **dialect_qnone)
+        self._write_test_vary_doublequote(fields, '"a//b","1"',
+                         **dialect_qall)
+
+        fields = ['/',2]
+        self._write_test_vary_doublequote(fields, '"//",2',
+                         **dialect_qminimal)
+        self._write_test_vary_doublequote(fields, '//,2',
+                         **dialect_qnone)
+        self._write_test_vary_doublequote(fields, '"//","2"',
+                         **dialect_qall)
+
+        fields = ['a',1,'p/q']
+        self._write_test_vary_doublequote(fields, 'a,1,"p//q"',
+                         **dialect_qminimal)
+        self._write_test_vary_doublequote(fields, 'a,1,p//q',
+                         **dialect_qnone)
+        self._write_test_vary_doublequote(fields, '"a","1","p//q"',
+                         **dialect_qall)
+
     def test_writerows(self):
         class BrokenFile:
             def write(self, buf):
diff -r 71a1f53c8203 -r 0eb420ce6567 Modules/_csv.c
--- a/Modules/_csv.c	Wed Jul 06 07:31:38 2011 +0200
+++ b/Modules/_csv.c	Wed Jul 06 23:02:13 2011 +0200
@@ -996,8 +996,11 @@
                     else
                         want_escape = 1;
                 }
-                if (!want_escape)
+                if (!want_escape) {
                     *quoted = 1;
+                    if (c == dialect->escapechar)
+                        want_escape = 1;
+                }
             }
             if (want_escape) {
                 if (!dialect->escapechar) {