diff --git a/md2resume_dev.php b/md2resume_dev.php
index a0fbe94..b1e4d11 100755
--- a/md2resume_dev.php
+++ b/md2resume_dev.php
@@ -16,7 +16,7 @@ $app->add('Resume', __DIR__ . '/src');
 $console = new Resume\Cli\Resume();
 
 // If we're running from phar, we get these values from the stub
-if (!defined("IN_PHAR")) {
+if (!defined('IN_PHAR')) {
     $project = json_decode(file_get_contents(__DIR__ . '/composer.json'));
 }
 
diff --git a/src/Resume/Cli/Resume.php b/src/Resume/Cli/Resume.php
index dc025ce..0e0a3f2 100644
--- a/src/Resume/Cli/Resume.php
+++ b/src/Resume/Cli/Resume.php
@@ -30,6 +30,9 @@ class Resume extends Application
         // the alternative is OutputInterface::OUTPUT_PLAIN;
         $this->outputFormat = OutputInterface::OUTPUT_NORMAL;
 
+        // Exits on missing dependencies
+        $this->checkDependencies();
+
         // We do this now because we've loaded the project info from the composer file
         $this->setName($this->project->description);
         $this->setVersion($this->project->version);
@@ -65,6 +68,18 @@ class Resume extends Application
         return parent::getLongVersion().' by <comment>Craig Davis</comment>';
     }
 
+    public function checkDependencies() {
+        $output = new ConsoleOutput();
+        if (!extension_loaded('mbstring')) {
+            $output->writeln(
+                "\n<error>Missing Dependency: Please install the Multibyte String Functions.</error>\n" .
+                "More help: http://www.php.net/manual/en/mbstring.installation.php\n",
+                $this->outputFormat
+            );
+        exit(1);
+        }
+    }
+
     public function registerStyles(&$output)
     {
         // https://github.com/symfony/Console/blob/master/Formatter/OutputFormatterStyle.php