diff --git a/includes/create-theme/theme-readme.php b/includes/create-theme/theme-readme.php
index ae303bde..2da3b57c 100644
--- a/includes/create-theme/theme-readme.php
+++ b/includes/create-theme/theme-readme.php
@@ -97,6 +97,9 @@ public static function create( $theme ) {
 		// Adds the Images section
 		$readme_content = self::add_or_update_section( 'Images', $image_credits, $readme_content );
 
+		// Sanitize the readme content
+		$readme_content = self::sanitize( $readme_content );
+
 		return $readme_content;
 	}
 
@@ -229,6 +232,9 @@ public static function update( $theme, $readme_content = '' ) {
 		// Update image credits section.
 		$readme_content = self::add_or_update_section( 'Images', $image_credits, $readme_content );
 
+		// Sanitize the readme content.
+		$readme_content = self::sanitize( $readme_content );
+
 		return $readme_content;
 	}
 
@@ -339,4 +345,16 @@ public static function get_sections() {
 		return $sections;
 	}
 
+	/**
+	 * Sanitize the readme content.
+	 *
+	 * @param string $readme_content The readme content.
+	 * @return string The sanitized readme content.
+	 */
+	private static function sanitize( $readme_content ) {
+		// Replaces DOS line endings with Unix line endings
+		$readme_content = str_replace( "\r\n", '', $readme_content );
+		return $readme_content;
+	}
+
 }
diff --git a/tests/CbtThemeReadme/base.php b/tests/CbtThemeReadme/base.php
index 2200c4dd..1acd9e97 100644
--- a/tests/CbtThemeReadme/base.php
+++ b/tests/CbtThemeReadme/base.php
@@ -61,4 +61,18 @@ public function tear_down() {
 		// Restore the original active theme.
 		switch_theme( $this->orig_active_theme_slug );
 	}
+
+	/**
+	 * Removes the newlines from a string.
+	 *
+	 * This is useful to make it easier to search for strings in the readme content.
+	 * Removes both DOS and Unix newlines.
+	 *
+	 * @param string $string
+	 * @return string
+	 */
+	public function remove_newlines( $string ) {
+		return str_replace( array( "\r\n", "\n" ), '', $string );
+	}
+
 }
diff --git a/tests/CbtThemeReadme/create.php b/tests/CbtThemeReadme/create.php
index 7f9b6798..6faff42c 100644
--- a/tests/CbtThemeReadme/create.php
+++ b/tests/CbtThemeReadme/create.php
@@ -17,8 +17,11 @@ class CBT_ThemeReadme_Create extends CBT_Theme_Readme_UnitTestCase {
 	public function test_create( $data ) {
 		$readme = CBT_Theme_Readme::create( $data );
 
+		// Check sanitazion before altering the content.
+		$this->assertStringNotContainsString( "\r\n", $readme, 'The readme content contains DOS newlines.' );
+
 		// Removes the newlines from the readme content to make it easier to search for strings.
-		$readme_without_newlines = str_replace( "\n", '', $readme );
+		$readme_without_newlines = $this->remove_newlines( $readme );
 
 		$expected_name                = '== ' . $data['name'] . ' ==';
 		$expected_description         = '== Description ==' . $data['description'];
@@ -30,10 +33,16 @@ public function test_create( $data ) {
 		$expected_license             = 'License: ' . $data['license'];
 		$expected_license_uri         = 'License URI: ' . $data['license_uri'];
 		$expected_font_credits        = '== Fonts ==' .
-			( isset( $data['font_credits'] ) ? $data['font_credits'] : '' );
+			( isset( $data['font_credits'] )
+				? $this->remove_newlines( $data['font_credits'] )
+				: ''
+			);
 		$expected_image_credits       = '== Images ==' .
-			( isset( $data['image_credits'] ) ? $data['image_credits'] : '' );
-		$expected_recommended_plugins = '== Recommended Plugins ==' . $data['recommended_plugins'];
+			( isset( $data['image_credits'] )
+				? $this->remove_newlines( $data['image_credits'] )
+				: ''
+			);
+		$expected_recommended_plugins = '== Recommended Plugins ==' . $this->remove_newlines( $data['recommended_plugins'] );
 
 		$this->assertStringContainsString( $expected_name, $readme_without_newlines, 'The expected name is missing.' );
 		$this->assertStringContainsString( $expected_author, $readme_without_newlines, 'The expected author is missing.' );
@@ -161,6 +170,27 @@ public function data_test_create() {
 					'font_credits'         => 'Font credit example text',
 				),
 			),
+			/*
+			 * This string contains DOS newlines.
+			 * It uses double quotes to make PHP interpret the newlines as newlines and not as string literals.
+			 */
+			'With DOS newlines'                => array(
+				'data' => array(
+					'name'                 => 'My Theme',
+					'description'          => 'New theme description',
+					'uri'                  => 'https://example.com',
+					'author'               => 'New theme author',
+					'author_uri'           => 'https://example.com/author',
+					'copyright_year'       => '2077',
+					'wp_version'           => '12.12',
+					'required_php_version' => '10.0',
+					'license'              => 'GPLv2 or later',
+					'license_uri'          => 'https://www.gnu.org/licenses/gpl-2.0.html',
+					'image_credits'        => "New image credits \r\n New image credits 2",
+					'recommended_plugins'  => "Plugin1 \r\n Plugin2 \r\n Plugin3",
+					'font_credits'         => "Font1 \r\n Font2 \r\n Font3",
+				),
+			),
 			// TODO: Add more test cases.
 		);
 	}
diff --git a/tests/CbtThemeReadme/update.php b/tests/CbtThemeReadme/update.php
index 158736fd..d6ca9012 100644
--- a/tests/CbtThemeReadme/update.php
+++ b/tests/CbtThemeReadme/update.php
@@ -18,13 +18,16 @@ public function test_update( $data ) {
 		$readme_content = CBT_Theme_Readme::get_content();
 		$readme         = CBT_Theme_Readme::update( $data, $readme_content );
 
+		// Check sanitazion before altering the content.
+		$this->assertStringNotContainsString( "\r\n", $readme, 'The readme content contains DOS newlines.' );
+
 		// Removes the newlines from the readme content to make it easier to search for strings.
-		$readme_without_newlines = str_replace( "\n", '', $readme );
+		$readme_without_newlines = $this->remove_newlines( $readme );
 
 		$expected_author              = 'Contributors: ' . $data['author'];
 		$expected_wp_version          = 'Tested up to: ' . $data['wp_version'] ?? CBT_Theme_Utils::get_current_wordpress_version();
-		$expected_image_credits       = '== Images ==' . $data['image_credits'];
-		$expected_recommended_plugins = '== Recommended Plugins ==' . $data['recommended_plugins'];
+		$expected_image_credits       = '== Images ==' . $this->remove_newlines( $data['image_credits'] );
+		$expected_recommended_plugins = '== Recommended Plugins ==' . $this->remove_newlines( $data['recommended_plugins'] );
 
 		$this->assertStringContainsString( $expected_author, $readme_without_newlines, 'The expected author is missing.' );
 		$this->assertStringContainsString( $expected_wp_version, $readme_without_newlines, 'The expected WP version is missing.' );
@@ -33,7 +36,7 @@ public function test_update( $data ) {
 
 		// Assertion specific to font credits.
 		if ( isset( $data['font_credits'] ) ) {
-			$expected_font_credits = '== Fonts ==' . $data['font_credits'];
+			$expected_font_credits = '== Fonts ==' . $this->remove_newlines( $data['font_credits'] );
 			$this->assertStringContainsString( $expected_font_credits, $readme_without_newlines, 'The expected font credits are missing.' );
 		}
 	}
@@ -59,7 +62,20 @@ public function data_test_update() {
 					'recommended_plugins' => 'New recommended plugins',
 				),
 			),
-			// TODO: Add more test cases.
+			/*
+			 * This string contains DOS newlines.
+			 * It uses double quotes to make PHP interpret the newlines as newlines and not as string literals.
+			 */
+			'Remove DOS newlines'  => array(
+				'data' => array(
+					'description'         => 'New theme description',
+					'author'              => 'New theme author',
+					'wp_version'          => '12.12',
+					'image_credits'       => "New image credits \r\n New image credits 2",
+					'recommended_plugins' => "Plugin1 \r\n Plugin2 \r\n Plugin3",
+					'font_credits'        => "Font1 \r\n Font2 \r\n Font3",
+				),
+			),
 		);
 	}
 }