diff --git a/README.md b/README.md
index 5adffbe7..1e456b90 100644
--- a/README.md
+++ b/README.md
@@ -32,10 +32,12 @@ FLAGS:
     -V, --version            Prints version information
 
 OPTIONS:
-    -e, --extension <EXTENSION>...    Specify an extension name to use [values: strikethrough, tagfilter, table, autolink, tasklist, superscript, footnotes]
-    -t, --to <FORMAT>                 Specify output format [default: html]  [values: html, commonmark]
-        --header-ids <PREFIX>         Use the Comrak header IDs extension, with the given ID prefix
-        --width <WIDTH>               Specify wrap width (0 = nowrap) [default: 0]
+        --default-info-string <INFO>    Default value for fenced code block's info strings if none is given
+    -e, --extension <EXTENSION>...      Specify an extension name to use [values: strikethrough, tagfilter, table,
+                                        autolink, tasklist, superscript, footnotes]
+    -t, --to <FORMAT>                   Specify output format [default: html]  [values: html, commonmark]
+        --header-ids <PREFIX>           Use the Comrak header IDs extension, with the given ID prefix
+        --width <WIDTH>                 Specify wrap width (0 = nowrap) [default: 0]
 
 ARGS:
     <FILE>...    The CommonMark file to parse; or standard input if none passed
diff --git a/src/main.rs b/src/main.rs
index 3961d554..61d6feab 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -54,6 +54,13 @@ fn main() {
                 .long("github-pre-lang")
                 .help("Use GitHub-style <pre lang> for code blocks"),
         )
+        .arg(
+            clap::Arg::with_name("default-info-string")
+                .long("default-info-string")
+                .help("Default value for fenced code block's info strings if none is given")
+                .value_name("INFO")
+                .takes_value(true)
+        )
         .arg(
             clap::Arg::with_name("extension")
                 .short("e")
@@ -117,6 +124,9 @@ fn main() {
             .unwrap_or("0")
             .parse()
             .unwrap_or(0),
+        default_info_string: matches
+            .value_of("default-info-string")
+            .map(|e| e.to_owned()),
         ext_strikethrough: exts.remove("strikethrough"),
         ext_tagfilter: exts.remove("tagfilter"),
         ext_table: exts.remove("table"),
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index f106dca9..6a09349f 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -119,6 +119,20 @@ pub struct ComrakOptions {
     /// ```
     pub width: usize,
 
+    /// The default info string for fenced code blocks.
+    ///
+    /// ```
+    /// # use comrak::{markdown_to_html, ComrakOptions};
+    /// let mut options = ComrakOptions::default();
+    /// assert_eq!(markdown_to_html("```\nfn hello();\n```\n", &options),
+    ///            "<pre><code>fn hello();\n</code></pre>\n");
+    ///
+    /// options.default_info_string = Some("rust".into());
+    /// assert_eq!(markdown_to_html("```\nfn hello();\n```\n", &options),
+    ///            "<pre><code class=\"language-rust\">fn hello();\n</code></pre>\n");
+    /// ```
+    pub default_info_string: Option<String>,
+
     /// Enables the
     /// [strikethrough extension](https://github.github.com/gfm/#strikethrough-extension-)
     /// from the GFM spec.
@@ -1062,7 +1076,14 @@ impl<'a, 'o> Parser<'a, 'o> {
                     let mut tmp = entity::unescape_html(&content[..pos]);
                     strings::trim(&mut tmp);
                     strings::unescape(&mut tmp);
-                    ncb.info = tmp;
+                    if tmp.is_empty() {
+                        ncb.info = self.options
+                            .default_info_string
+                            .as_ref()
+                            .map_or(vec![], |s| s.as_bytes().to_vec());
+                    } else {
+                        ncb.info = tmp;
+                    }
 
                     if content[pos] == b'\r' {
                         pos += 1;