diff --git a/src/wp-includes/formatting.php b/src/wp-includes/formatting.php
index 13fd350b62..ddce906aa6 100644
--- a/src/wp-includes/formatting.php
+++ b/src/wp-includes/formatting.php
@@ -469,7 +469,7 @@ function wpautop( $pee, $br = true ) {
 	$allblocks = '(?:table|thead|tfoot|caption|col|colgroup|tbody|tr|td|th|div|dl|dd|dt|ul|ol|li|pre|form|map|area|blockquote|address|math|style|p|h[1-6]|hr|fieldset|legend|section|article|aside|hgroup|header|footer|nav|figure|figcaption|details|menu|summary)';
 
 	// Add a single line break above block-level opening tags.
-	$pee = preg_replace('!(<' . $allblocks . '[\s/>])!', "\n$1", $pee);
+	$pee = preg_replace('!(<' . $allblocks . '[\s/>])!', "\n\n$1", $pee);
 
 	// Add a double line break below block-level closing tags.
 	$pee = preg_replace('!(</' . $allblocks . '>)!', "$1\n\n", $pee);
diff --git a/tests/phpunit/tests/formatting/Autop.php b/tests/phpunit/tests/formatting/Autop.php
index ccc0d3ac48..62251d78ca 100644
--- a/tests/phpunit/tests/formatting/Autop.php
+++ b/tests/phpunit/tests/formatting/Autop.php
@@ -524,4 +524,14 @@ line 2<br/>
 		$this->assertEquals( $expected, trim( wpautop( $content ) ) );
 	}
 
+
+	/**
+	 * @ticket 4857
+	 */
+	function test_that_text_before_blocks_is_peed() {
+		$content = 'a<div>b</div>';
+		$expected = "<p>a</p>\n<div>b</div>";
+
+		$this->assertEquals( $expected, trim( wpautop( $content ) ) );
+	}
 }