diff --git a/examples/deASCIIdeCrypt.php b/examples/deASCIIdeCrypt.php
index b346a89..9ab6cdd 100644
--- a/examples/deASCIIdeCrypt.php
+++ b/examples/deASCIIdeCrypt.php
@@ -3,9 +3,9 @@
 // USAGE: php examples/deASCIIdeCrypt.php secretkey.asc password message.asc
 // This will fail if the algo on key or message is not 3DES or AES
 
-require dirname(__FILE__).'/../lib/openpgp.php';
-require dirname(__FILE__).'/../lib/openpgp_crypt_rsa.php';
-require dirname(__FILE__).'/../lib/openpgp_crypt_symmetric.php';
+require_once dirname(__FILE__).'/../lib/openpgp.php';
+require_once dirname(__FILE__).'/../lib/openpgp_crypt_rsa.php';
+require_once dirname(__FILE__).'/../lib/openpgp_crypt_symmetric.php';
 
 $keyASCII = file_get_contents($argv[1]);
 $msgASCII = file_get_contents($argv[3]);
diff --git a/examples/encryptDecrypt.php b/examples/encryptDecrypt.php
index 88649ba..70b2fbf 100644
--- a/examples/encryptDecrypt.php
+++ b/examples/encryptDecrypt.php
@@ -1,8 +1,8 @@
 <?php
 
-require dirname(__FILE__).'/../lib/openpgp.php';
-require dirname(__FILE__).'/../lib/openpgp_crypt_rsa.php';
-require dirname(__FILE__).'/../lib/openpgp_crypt_symmetric.php';
+require_once dirname(__FILE__).'/../lib/openpgp.php';
+require_once dirname(__FILE__).'/../lib/openpgp_crypt_rsa.php';
+require_once dirname(__FILE__).'/../lib/openpgp_crypt_symmetric.php';
 
 $key = OpenPGP_Message::parse(file_get_contents(dirname(__FILE__) . '/../tests/data/helloKey.gpg'));
 $data = new OpenPGP_LiteralDataPacket('This is text.', array('format' => 'u', 'filename' => 'stuff.txt'));
diff --git a/examples/keygen.php b/examples/keygen.php
index f0a8b56..4dd61f7 100644
--- a/examples/keygen.php
+++ b/examples/keygen.php
@@ -1,7 +1,7 @@
 <?php
 
-require dirname(__FILE__).'/../lib/openpgp.php';
-require dirname(__FILE__).'/../lib/openpgp_crypt_rsa.php';
+require_once dirname(__FILE__).'/../lib/openpgp.php';
+require_once dirname(__FILE__).'/../lib/openpgp_crypt_rsa.php';
 
 $rsa = new Crypt_RSA();
 $k = $rsa->createKey(512);
diff --git a/examples/sign.php b/examples/sign.php
index b22c81c..5e68d64 100644
--- a/examples/sign.php
+++ b/examples/sign.php
@@ -1,7 +1,7 @@
 <?php
 
-require dirname(__FILE__).'/../lib/openpgp.php';
-require dirname(__FILE__).'/../lib/openpgp_crypt_rsa.php';
+require_once dirname(__FILE__).'/../lib/openpgp.php';
+require_once dirname(__FILE__).'/../lib/openpgp_crypt_rsa.php';
 
 /* Parse secret key from STDIN, the key must not be password protected */
 $wkey = OpenPGP_Message::parse(file_get_contents('php://stdin'));