diff --git a/NEWS b/NEWS
index 7f2fe9dc824..4f7331246fd 100644
--- a/NEWS
+++ b/NEWS
@@ -16,6 +16,8 @@
 - Core:
   . Added ability to connect to HTTPS sites through proxy with basic
     authentication using stream_context/http/header/Proxy-Authorization (Dmitry)
+  . Changed default value of ini directive serialize_precision from 100 to 17.
+    (Gustavo)
   . Fixed bug #53959 (reflection data for fgetcsv out-of-date). (Richard)
   . Fixed bug #53577 (Regression introduced in 5.3.4 in open_basedir with a
     trailing forward slash). (lekensteyn at gmail dot com, Pierre)
diff --git a/ext/standard/tests/serialize/precision.phpt b/ext/standard/tests/serialize/precision.phpt
new file mode 100644
index 00000000000..142b2cecf81
--- /dev/null
+++ b/ext/standard/tests/serialize/precision.phpt
@@ -0,0 +1,49 @@
+--TEST--
+Default precision is sufficient to serialize all the information in floats
+--SKIPIF--
+<?php
+if (pack('s', 1) != "\x01\x00")
+	die("skip test for little-endian architectures");
+--FILE--
+<?php
+
+$numbers = array(
+	"0000000000000000", //0
+	"2d431cebe2362a3f", //.0002
+	"2e431cebe2362a3f", //.0002 + 10^-Accuracy[.0002]*1.01
+	"0000000000001000", //2^-1022. (minimum normal double)
+	"0100000000001000", //2^-1022. + 10^-Accuracy[2^-1022.]*1.01
+	"ffffffffffffef7f", //2^1024. (maximum normal double)
+	"feffffffffffef7f", //2^1024. - 10^-Accuracy[2^1024.]
+	"0100000000000000", //minumum subnormal double
+	"0200000000000000", //2nd minumum subnormal double
+	"fffffffffffff000", //maximum subnormal double
+	"fefffffffffff000", //2nd maximum subnormal double
+	"0000000000000f7f", //+inf
+	"0000000000000fff", //-inf
+);
+
+foreach ($numbers as $ns) {
+	$num = unpack("d", pack("H*", $ns)); $num = reset($num);
+	echo "number: ", sprintf("%.17e", $num), "... ";
+	$num2 = unserialize(serialize($num));
+	$repr = unpack("H*", pack("d", $num2)); $repr = reset($repr);
+	if ($repr == $ns)
+		echo "OK\n";
+	else
+		echo "mismatch\n\twas:    $ns\n\tbecame: $repr\n";
+}
+--EXPECT--
+number: 0.00000000000000000e+0... OK
+number: 2.00000000000000010e-4... OK
+number: 2.00000000000000037e-4... OK
+number: 2.22507385850720138e-308... OK
+number: 2.22507385850720188e-308... OK
+number: 1.79769313486231571e+308... OK
+number: 1.79769313486231551e+308... OK
+number: 4.94065645841246544e-324... OK
+number: 9.88131291682493088e-324... OK
+number: 3.87340857288933536e-304... OK
+number: 3.87340857288933455e-304... OK
+number: 1.06293653832877718e+304... OK
+number: -1.06293653832877718e+304... OK
diff --git a/main/main.c b/main/main.c
index afae42c4316..3fee30f5ba9 100644
--- a/main/main.c
+++ b/main/main.c
@@ -477,7 +477,7 @@ PHP_INI_BEGIN()
 	STD_PHP_INI_BOOLEAN("y2k_compliance",		"1",		PHP_INI_ALL,		OnUpdateBool,			y2k_compliance,			php_core_globals,	core_globals)
 
 	STD_PHP_INI_ENTRY("unserialize_callback_func",	NULL,	PHP_INI_ALL,		OnUpdateString,			unserialize_callback_func,	php_core_globals,	core_globals)
-	STD_PHP_INI_ENTRY("serialize_precision",	"100",	PHP_INI_ALL,		OnUpdateLongGEZero,			serialize_precision,	php_core_globals,	core_globals)
+	STD_PHP_INI_ENTRY("serialize_precision",	"17",	PHP_INI_ALL,		OnUpdateLongGEZero,			serialize_precision,	php_core_globals,	core_globals)
 	STD_PHP_INI_ENTRY("arg_separator.output",	"&",		PHP_INI_ALL,		OnUpdateStringUnempty,	arg_separator.output,	php_core_globals,	core_globals)
 	STD_PHP_INI_ENTRY("arg_separator.input",	"&",		PHP_INI_SYSTEM|PHP_INI_PERDIR,	OnUpdateStringUnempty,	arg_separator.input,	php_core_globals,	core_globals)