diff --git a/src/playlist.rs b/src/playlist.rs
index 429e835..0ee58e7 100644
--- a/src/playlist.rs
+++ b/src/playlist.rs
@@ -69,7 +69,8 @@ pub struct MasterPlaylist {
     pub session_key: Option<SessionKey>,
     pub start: Option<Start>,
     pub independent_segments: bool,
-    pub alternatives: Vec<AlternativeMedia> // EXT-X-MEDIA tags
+    pub alternatives: Vec<AlternativeMedia>, // EXT-X-MEDIA tags
+    pub unknown_tags: Vec<ExtTag>
 }
 
 impl MasterPlaylist {
@@ -105,8 +106,8 @@ impl MasterPlaylist {
                 MasterPlaylistTag::IndependentSegments => {
                     master_playlist.independent_segments = true;
                 }
-                MasterPlaylistTag::Unknown(_) => {
-                    // println!("Unknown master tag \n{:?}\n", t);
+                MasterPlaylistTag::Unknown(unknown) => {
+                    master_playlist.unknown_tags.push(unknown);
                 }
                 _ => (),
             }
@@ -142,6 +143,9 @@ impl MasterPlaylist {
         if self.independent_segments {
             writeln!(w, "#EXT-X-INDEPENDENT-SEGMENTS")?;
         }
+        for unknown_tag in &self.unknown_tags {
+            write!(w, "#EXT-{}:{}\n", unknown_tag.tag, unknown_tag.rest)?;
+        }
 
         Ok(())
     }
@@ -405,6 +409,8 @@ pub struct MediaPlaylist {
     pub start: Option<Start>,
     /// `#EXT-X-INDEPENDENT-SEGMENTS`
     pub independent_segments: bool,
+    /// `#EXT-X-` 
+    pub unknown_tags: Vec<ExtTag>
 }
 
 impl MediaPlaylist {
@@ -469,6 +475,9 @@ impl MediaPlaylist {
                         SegmentTag::DateRange(d) => {
                             next_segment.daterange = Some(d);
                         }
+                        SegmentTag::Unknown(t) => {
+                            media_playlist.unknown_tags.push(t);
+                        }
                         SegmentTag::Uri(u) => {
                             next_segment.key = encryption_key.clone();
                             next_segment.map = map.clone();
@@ -516,6 +525,9 @@ impl MediaPlaylist {
         for segment in &self.segments {
             segment.write_to(w)?;
         }
+        for unknown_tag in &self.unknown_tags {
+            write!(w, "#EXT-{}:{}\n", unknown_tag.tag, unknown_tag.rest)?;
+        }
 
         Ok(())
     }
@@ -789,8 +801,9 @@ impl Start {
 }
 
 /// A simple `#EXT-` tag
-#[derive(Debug, Default, Clone)]
+#[derive(Debug, Default, PartialEq, Clone)]
 pub struct ExtTag {
     pub tag: String,
     pub rest: String,
 }
+
diff --git a/tests/lib.rs b/tests/lib.rs
index 9d09162..bf88f21 100644
--- a/tests/lib.rs
+++ b/tests/lib.rs
@@ -130,7 +130,7 @@ fn playlist_types() {
 
         println!("{:?} = {:?}", path, is_master);
 
-        assert!(path.to_lowercase().contains("master") == is_master);     
+        assert!(path.to_lowercase().contains("master") == is_master);
     }
 }
 
@@ -191,7 +191,7 @@ fn test_key_value_pair() {
         Result::Ok((
             "rest".as_bytes(),
             ("PROGRAM-ID".to_string(), "1".to_string())
-        )) 
+        ))
     );
 }
 
@@ -276,9 +276,9 @@ fn print_create_and_parse_playlist(playlist_original: &mut Playlist) -> Playlist
     let m3u8_str: &str = std::str::from_utf8(&utf8).unwrap();
 
     let playlist_parsed = match *playlist_original {
-        Playlist::MasterPlaylist(_) => 
+        Playlist::MasterPlaylist(_) =>
             Playlist::MasterPlaylist(parse_master_playlist_res(m3u8_str.as_bytes()).unwrap()),
-        Playlist::MediaPlaylist(_) => 
+        Playlist::MediaPlaylist(_) =>
             Playlist::MediaPlaylist(parse_media_playlist_res(m3u8_str.as_bytes()).unwrap()),
     };
 
@@ -336,8 +336,8 @@ fn create_and_parse_master_playlist_full() {
             data_id: "****".into(),
             value: "%%%%".into(),
             uri: "++++".into(),
-            language: Some("SessionDataLanguage".into()),    
-        }),  
+            language: Some("SessionDataLanguage".into()),
+        }),
         session_key: Some(SessionKey(Key {
             method: "AES-128".into(),
             uri: Some("https://secure.domain.com".into()),
@@ -350,6 +350,7 @@ fn create_and_parse_master_playlist_full() {
             precise: Some("YES".into()),
         }),
         independent_segments: true,
+        unknown_tags: vec![],
     });
     let playlist_parsed = print_create_and_parse_playlist(&mut playlist_original);
     assert_eq!(playlist_original, playlist_parsed);
@@ -364,7 +365,7 @@ fn create_and_parse_media_playlist_empty() {
 
 #[test]
 fn create_and_parse_media_playlist_single_segment() {
-    let mut playlist_original = Playlist::MediaPlaylist(MediaPlaylist { 
+    let mut playlist_original = Playlist::MediaPlaylist(MediaPlaylist {
         segments: vec![
             MediaSegment {
                 uri: "20140311T113819-01-338559live.ts".into(),
@@ -394,7 +395,7 @@ fn create_and_parse_media_playlist_full() {
             time_offset: "9999".into(),
             precise: Some("YES".into()),
         }),
-        independent_segments: true,     
+        independent_segments: true,
         segments: vec![
             MediaSegment {
                 uri: "20140311T113819-01-338559live.ts".into(),
@@ -408,7 +409,7 @@ fn create_and_parse_media_playlist_full() {
                     iv: Some("0xb059217aa2649ce170b734".into()),
                     keyformat: Some("xXkeyformatXx".into()),
                     keyformatversions: Some("xXFormatVers".into()),
-                }), 
+                }),
                 map: Some(Map {
                     uri: "www.map-uri.com".into(),
                     byte_range: Some(ByteRange::from("137116@497036")),
@@ -417,6 +418,7 @@ fn create_and_parse_media_playlist_full() {
                 daterange: None,
             },
         ],
+        unknown_tags: vec![],
     });
     let playlist_parsed = print_create_and_parse_playlist(&mut playlist_original);
     assert_eq!(playlist_original, playlist_parsed);
@@ -439,7 +441,7 @@ fn parsing_write_to_should_produce_the_same_structure() {
 
         assert_eq!(
             expected, actual,
-            "\n\nFailed parser input:\n\n{}\n\nOriginal input:\n\n{}", 
+            "\n\nFailed parser input:\n\n{}\n\nOriginal input:\n\n{}",
             std::str::from_utf8(&written).unwrap(), input);
     }
 }