diff --git a/src/elements/section.rs b/src/elements/section.rs
index 1538add..7109e86 100644
--- a/src/elements/section.rs
+++ b/src/elements/section.rs
@@ -257,6 +257,10 @@ impl Deserialize for CodeSection {
 pub struct ElementSection(Vec<ElementSegment>);
 
 impl ElementSection {
+    pub fn new(entries: Vec<ElementSegment>) -> Self {
+        ElementSection(entries)
+    }
+
     pub fn entries(&self) -> &[ElementSegment] {
         &self.0
     }
@@ -273,6 +277,22 @@ impl Deserialize for ElementSection {
     }   
 }
 
+impl Serialize for ElementSection {
+    type Error = Error;
+    
+    fn serialize<W: io::Write>(self, writer: &mut W) -> Result<(), Self::Error> {
+        let mut counted_writer = CountedWriter::new(writer);
+        let data = self.0;
+        let counted_list = CountedListWriter::<ElementSegment, _>(
+            data.len(),
+            data.into_iter().map(Into::into),
+        );
+        counted_list.serialize(&mut counted_writer)?;
+        counted_writer.done()?;
+        Ok(())
+    }
+}
+
 pub struct DataSection(Vec<DataSegment>);
 
 impl DataSection {
@@ -317,9 +337,9 @@ mod tests {
 
     use super::super::{
         deserialize_buffer, deserialize_file, ValueType, InitExpr, DataSegment,
-        serialize,
+        serialize, ElementSegment,
     };
-    use super::{Section, TypeSection, Type, DataSection};
+    use super::{Section, TypeSection, Type, DataSection, ElementSection};
 
     #[test]
     fn import_section() {
@@ -555,10 +575,11 @@ mod tests {
         let buf = serialize(data_section).expect("Data section to be serialized");
 
         assert_eq!(buf, vec![
-            19u8, // 19 bytes overall
+            20u8, // 19 bytes overall
             0x01, // number of segments
             0x00, // index
             0x0b, // just `end` op
+            16,   // value of length 16
             0x00, 0x00, 0x00, 0x00, // 16x 0x00 as in initialization
             0x00, 0x00, 0x00, 0x00,
             0x00, 0x00, 0x00, 0x00,
@@ -578,4 +599,22 @@ mod tests {
             }
         }
     }
+
+    #[test]
+    fn element_section_ser() {
+        let element_section = ElementSection::new(
+            vec![ElementSegment::new(0u32, InitExpr::empty(), vec![0u32; 4])]
+        );
+
+        let buf = serialize(element_section).expect("Data section to be serialized");
+
+        assert_eq!(buf, vec![
+            08u8, // 8 bytes overall
+            0x01, // number of segments
+            0x00, // index
+            0x0b, // just `end` op
+            0x04, // 4 elements
+            0x00, 0x00, 0x00, 0x00 // 4x 0x00 as in initialization
+        ]);
+    }    
 }
\ No newline at end of file
diff --git a/src/elements/segment.rs b/src/elements/segment.rs
index d7fde04..d849e5a 100644
--- a/src/elements/segment.rs
+++ b/src/elements/segment.rs
@@ -1,5 +1,5 @@
 use std::io;
-use super::{Deserialize, Serialize, Error, VarUint32, CountedList, InitExpr};
+use super::{Deserialize, Serialize, Error, VarUint32, CountedList, InitExpr, CountedListWriter};
 
 pub struct ElementSegment {
     index: u32,
@@ -8,8 +8,14 @@ pub struct ElementSegment {
 }
 
 impl ElementSegment {
+    pub fn new(index: u32, offset: InitExpr, members: Vec<u32>) -> Self {
+        ElementSegment { index: index, offset: offset, members: members }
+    }
+
     pub fn members(&self) -> &[u32] { &self.members }
+
     pub fn index(&self) -> u32 { self.index }
+
     pub fn offset(&self) -> &InitExpr { &self.offset }
 }
 
@@ -33,6 +39,22 @@ impl Deserialize for ElementSegment {
     }   
 }
 
+impl Serialize for ElementSegment {
+    type Error = Error;
+    
+    fn serialize<W: io::Write>(self, writer: &mut W) -> Result<(), Self::Error> {
+        VarUint32::from(self.index).serialize(writer)?;
+        self.offset.serialize(writer)?;
+        let data = self.members;
+        let counted_list = CountedListWriter::<VarUint32, _>(
+            data.len(),
+            data.into_iter().map(Into::into),
+        );        
+        counted_list.serialize(writer)?;        
+        Ok(())
+    }
+}
+
 pub struct DataSegment {
     index: u32,
     offset: InitExpr,
@@ -78,7 +100,10 @@ impl Serialize for DataSegment {
     fn serialize<W: io::Write>(self, writer: &mut W) -> Result<(), Self::Error> {
         VarUint32::from(self.index).serialize(writer)?;
         self.offset.serialize(writer)?;
-        writer.write_all(&self.value[..])?;
+
+        let value = self.value;
+        VarUint32::from(value.len()).serialize(writer)?;
+        writer.write_all(&value[..])?;
         Ok(())
     }
 }
\ No newline at end of file