diff --git a/string/Makefile b/string/Makefile
index c84b49aaa5..472e318aea 100644
--- a/string/Makefile
+++ b/string/Makefile
@@ -157,6 +157,7 @@ tests := \
   test-strcmp \
   test-strcpy \
   test-strcspn \
+  test-strdup \
   test-strlen \
   test-strncasecmp \
   test-strncat \
diff --git a/string/test-strdup.c b/string/test-strdup.c
new file mode 100644
index 0000000000..9378c7eaf0
--- /dev/null
+++ b/string/test-strdup.c
@@ -0,0 +1,201 @@
+/* Test and measure strdup functions.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/check.h>
+
+#ifdef WIDE
+# include <wchar.h>
+# define CHAR wchar_t
+# define sfmt "ls"
+# define BIG_CHAR WCHAR_MAX
+# define SMALL_CHAR 1273
+# define STRCMP wcscmp
+# define MEMCMP wmemcmp
+# define MEMSET wmemset
+# define TCS TEST_COMPARE_STRING_WIDE
+#else
+# define CHAR char
+# define sfmt "s"
+# define BIG_CHAR CHAR_MAX
+# define SMALL_CHAR 127
+# define STRCMP strcmp
+# define MEMCMP memcmp
+# define MEMSET memset
+# define TCS TEST_COMPARE_STRING
+#endif
+
+#ifndef STRDUP_RESULT
+# define STRDUP_RESULT(dst, len) dst
+# define TEST_MAIN
+# ifndef WIDE
+#  define TEST_NAME "strdup"
+# else
+#  define TEST_NAME "wcsdup"
+# endif
+# include "test-string.h"
+# ifndef WIDE
+#  define STRDUP strdup
+# else
+#  define STRDUP wcsdup
+# endif
+#endif
+
+typedef CHAR *(*proto_t) (const CHAR *);
+
+static void
+do_zero_len_test (void)
+{
+  CHAR src[1] = { '\0' };
+  CHAR *dst = STRDUP (src);
+
+  TCS (dst, src);
+  free (dst);
+}
+
+static void
+do_one_test (const CHAR *src,
+	     size_t len __attribute__((unused)))
+{
+  CHAR *dst = STRDUP (src);
+
+  if (STRCMP (dst, src) != 0)
+    {
+      error (0, 0,
+	     "Wrong result in function %s dst \"%" sfmt "\" src \"%" sfmt "\"",
+	     TEST_NAME, dst, src);
+      ret = 1;
+      free (dst);
+      return;
+    }
+  free (dst);
+}
+
+static void
+do_test (size_t align1, size_t align2, size_t len, int max_char)
+{
+  size_t i;
+  CHAR *s1;
+/* For wcsdup: align1 and align2 here mean alignment not in bytes,
+   but in wchar_ts, in bytes it will equal to align * (sizeof (wchar_t))
+   len for wcschr here isn't in bytes but it's number of wchar_t symbols.  */
+  align1 &= 7;
+  if ((align1 + len) * sizeof (CHAR) >= page_size)
+    return;
+
+  align2 &= 7;
+  if ((align2 + len) * sizeof (CHAR) >= page_size)
+    return;
+
+  s1 = (CHAR *) (buf1) + align1;
+
+  for (i = 0; i < len; i++)
+    s1[i] = 32 + 23 * i % (max_char - 32);
+  s1[len] = 0;
+
+  do_one_test (s1, len);
+}
+
+static void
+do_random_tests (void)
+{
+  size_t i, j, n, align1, align2, len;
+  CHAR *p1 = (CHAR *)(buf1 + page_size) - 512;
+  CHAR *res;
+
+  for (n = 0; n < ITERATIONS; n++)
+    {
+      /* align1 and align2 are expressed as wchar_t and not in bytes for wide
+     char test, and thus it will be equal to align times wchar_t size.
+
+     For non wide version we need to check all alignments from 0 to 63
+     since some assembly implementations have separate prolog for alignments
+     more 48.  */
+
+      align1 = random () & (63 / sizeof (CHAR));
+      if (random () & 1)
+	align2 = random () & (63 / sizeof (CHAR));
+      else
+	align2 = align1 + (random () & 24);
+      len = random () & 511;
+      j = align1;
+      if (align2 > j)
+	j = align2;
+      if (len + j >= 511)
+	len = 510 - j - (random () & 7);
+      j = len + align1 + 64;
+      if (j > 512)
+	j = 512;
+      for (i = 0; i < j; i++)
+	{
+	  if (i == len + align1)
+	    p1[i] = 0;
+	  else
+	    {
+	      p1[i] = random () & BIG_CHAR;
+	      if (i >= align1 && i < len + align1 && !p1[i])
+		p1[i] = (random () & SMALL_CHAR) + 3;
+	    }
+	}
+
+      res =  STRDUP(p1 + align1);
+      TCS (res, (p1 + align1));
+      free (res);
+    }
+}
+
+
+int
+test_main (void)
+{
+  size_t i;
+
+  test_init ();
+
+  printf ("%23s", "");
+  printf ("\t%s", TEST_NAME);
+  putchar ('\n');
+
+  for (i = 0; i < 16; ++i)
+    {
+      do_test (0, 0, i, SMALL_CHAR);
+      do_test (0, 0, i, BIG_CHAR);
+      do_test (0, i, i, SMALL_CHAR);
+      do_test (i, 0, i, BIG_CHAR);
+    }
+
+  for (i = 1; i < 8; ++i)
+    {
+      do_test (0, 0, 8 << i, SMALL_CHAR);
+      do_test (8 - i, 2 * i, 8 << i, SMALL_CHAR);
+    }
+
+  for (i = 1; i < 8; ++i)
+    {
+      do_test (i, 2 * i, 8 << i, SMALL_CHAR);
+      do_test (2 * i, i, 8 << i, BIG_CHAR);
+      do_test (i, i, 8 << i, SMALL_CHAR);
+      do_test (i, i, 8 << i, BIG_CHAR);
+    }
+
+  do_zero_len_test ();
+  do_random_tests ();
+
+  return ret;
+}
+
+#include <support/test-driver.c>