diff --git a/ext/date/lib/timelib.h b/ext/date/lib/timelib.h
index f5e75978353..866eaf3dd23 100644
--- a/ext/date/lib/timelib.h
+++ b/ext/date/lib/timelib.h
@@ -92,6 +92,8 @@ int timelib_apply_localtime(timelib_time *t, unsigned int localtime);
 void timelib_unixtime2gmt(timelib_time* tm, timelib_sll ts);
 void timelib_unixtime2local(timelib_time *tm, timelib_sll ts);
 void timelib_update_from_sse(timelib_time *tm);
+void timelib_set_timezone_from_offset(timelib_time *t, timelib_sll utc_offset);
+void timelib_set_timezone_from_abbr(timelib_time *t, timelib_abbr_info abbr_info);
 void timelib_set_timezone(timelib_time *t, timelib_tzinfo *tz);
 
 /* From parse_tz.c */
diff --git a/ext/date/lib/timelib_structs.h b/ext/date/lib/timelib_structs.h
index de75545c481..50333213560 100644
--- a/ext/date/lib/timelib_structs.h
+++ b/ext/date/lib/timelib_structs.h
@@ -142,6 +142,12 @@ typedef struct timelib_time {
 	                              *  2 TimeZone abbreviation */
 } timelib_time;
 
+typedef struct timelib_abbr_info {
+	timelib_sll  utc_offset;
+	char        *abbr;
+	int          dst;
+} timelib_abbr_info;
+
 typedef struct timelib_error_message {
 	int         position;
 	char        character;
diff --git a/ext/date/lib/unixtime2tm.c b/ext/date/lib/unixtime2tm.c
index eefbaa8f373..9870313fbce 100644
--- a/ext/date/lib/unixtime2tm.c
+++ b/ext/date/lib/unixtime2tm.c
@@ -214,6 +214,34 @@ void timelib_unixtime2local(timelib_time *tm, timelib_sll ts)
 	tm->have_zone = 1;
 }
 
+void timelib_set_timezone_from_offset(timelib_time *t, timelib_sll utc_offset)
+{
+	if (t->tz_abbr) {
+		free(t->tz_abbr);
+	}
+	t->tz_abbr = NULL;
+
+	t->z = utc_offset;
+	t->have_zone = 1;
+	t->zone_type = TIMELIB_ZONETYPE_OFFSET;
+	t->dst = 0;
+	t->tz_info = NULL;
+}
+
+void timelib_set_timezone_from_abbr(timelib_time *t, timelib_abbr_info abbr_info)
+{
+	if (t->tz_abbr) {
+		free(t->tz_abbr);
+	}
+	t->tz_abbr = strdup(abbr_info.abbr);
+
+	t->z = abbr_info.utc_offset;
+	t->have_zone = 1;
+	t->zone_type = TIMELIB_ZONETYPE_ABBR;
+	t->dst = abbr_info.dst;
+	t->tz_info = NULL;
+}
+
 void timelib_set_timezone(timelib_time *t, timelib_tzinfo *tz)
 {
 	timelib_time_offset *gmt_offset;
diff --git a/ext/date/php_date.c b/ext/date/php_date.c
index c069e0ccaef..0e21baffa61 100644
--- a/ext/date/php_date.c
+++ b/ext/date/php_date.c
@@ -3284,11 +3284,18 @@ static void php_date_timezone_set(zval *object, zval *timezone_object, zval *ret
 	dateobj = (php_date_obj *) zend_object_store_get_object(object TSRMLS_CC);
 	DATE_CHECK_INITIALIZED(dateobj->time, DateTime);
 	tzobj = (php_timezone_obj *) zend_object_store_get_object(timezone_object TSRMLS_CC);
-	if (tzobj->type != TIMELIB_ZONETYPE_ID) {
-		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Can only do this for zones with ID for now");
-		return;
+
+	switch (tzobj->type) {
+		case TIMELIB_ZONETYPE_OFFSET:
+			timelib_set_timezone_from_offset(dateobj->time, tzobj->tzi.utc_offset);
+			break;
+		case TIMELIB_ZONETYPE_ABBR:
+			timelib_set_timezone_from_abbr(dateobj->time, tzobj->tzi.z);
+			break;
+		case TIMELIB_ZONETYPE_ID:
+			timelib_set_timezone(dateobj->time, tzobj->tzi.tz);
+			break;
 	}
-	timelib_set_timezone(dateobj->time, tzobj->tzi.tz);
 	timelib_unixtime2local(dateobj->time, dateobj->time->sse);
 }
 
diff --git a/ext/date/php_date.h b/ext/date/php_date.h
index d4204ebd79b..d7343e02bcb 100644
--- a/ext/date/php_date.h
+++ b/ext/date/php_date.h
@@ -137,14 +137,9 @@ struct _php_timezone_obj {
 	int             initialized;
 	int             type;
 	union {
-		timelib_tzinfo *tz; /* TIMELIB_ZONETYPE_ID; */
-		timelib_sll     utc_offset; /* TIMELIB_ZONETYPE_OFFSET */
-		struct                      /* TIMELIB_ZONETYPE_ABBR */
-		{
-			timelib_sll  utc_offset;
-			char        *abbr;
-			int          dst;
-		} z;
+		timelib_tzinfo   *tz;         /* TIMELIB_ZONETYPE_ID */
+		timelib_sll       utc_offset; /* TIMELIB_ZONETYPE_OFFSET */
+		timelib_abbr_info z;          /* TIMELIB_ZONETYPE_ABBR */
 	} tzi;
 	HashTable *props;
 };
diff --git a/ext/date/tests/bug45543.phpt b/ext/date/tests/bug45543.phpt
new file mode 100644
index 00000000000..8e36e6287cd
--- /dev/null
+++ b/ext/date/tests/bug45543.phpt
@@ -0,0 +1,34 @@
+--TEST--
+Test for bug #45543: DateTime::setTimezone can not set timezones without ID.
+--INI--
+date.timezone=UTC
+--FILE--
+<?php
+$test_dates = array(
+	'2008-01-01 12:00:00 PDT',
+	'2008-01-01 12:00:00 +02:00',
+);
+
+foreach ($test_dates as $test_date)
+{
+	$d1 = new DateTime($test_date);
+	$d2 = new DateTime('2008-01-01 12:00:00 UTC');
+	echo $d1->format(DATE_ISO8601), PHP_EOL;
+	echo $d2->format(DATE_ISO8601), PHP_EOL;
+	$tz = $d1->getTimeZone();
+	$d2->setTimeZone($tz);
+	echo $d1->format(DATE_ISO8601), PHP_EOL;
+	echo $d2->format(DATE_ISO8601), PHP_EOL;
+	echo PHP_EOL;
+}
+--EXPECT--
+2008-01-01T12:00:00-0700
+2008-01-01T12:00:00+0000
+2008-01-01T12:00:00-0700
+2008-01-01T05:00:00-0700
+
+2008-01-01T12:00:00+0200
+2008-01-01T12:00:00+0000
+2008-01-01T12:00:00+0200
+2008-01-01T14:00:00+0200
+