diff --git a/.gitignore b/.gitignore
index 7e4a920..6fbd31e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,3 +18,4 @@ Cargo.lock
 
 # These are backup files generated by rustfmt
 **/*.rs.bk
+**/.idea
\ No newline at end of file
diff --git a/yaserde/tests/namespace.rs b/yaserde/tests/namespace.rs
index c6b5151..dce4606 100644
--- a/yaserde/tests/namespace.rs
+++ b/yaserde/tests/namespace.rs
@@ -468,3 +468,33 @@ fn struct_bad_namespace() {
     Err("bad namespace for book, found http://www.sample.com/ns/domain2".to_string())
   );
 }
+
+#[test]
+fn struct_default_namespace_no_prefix() {
+  init();
+
+  #[derive(Debug, PartialEq, YaDeserialize, YaSerialize)]
+  #[yaserde(
+  rename = "book",
+  namespace = "http://www.sample.com/ns/domain"
+  )]
+  pub struct Book {
+    author: String,
+    title: String,
+  }
+
+  let content = r#"
+    <book xmlns="http://www.sample.com/ns/domain">
+      <author>Antoine de Saint-Exupéry</author>
+      <title>Little prince</title>
+    </book>
+  "#;
+
+  let model = Book {
+    author: "Antoine de Saint-Exupéry".to_owned(),
+    title: "Little prince".to_owned(),
+  };
+
+  serialize_and_validate!(model, content);
+  deserialize_and_validate!(content, model, Book);
+}
\ No newline at end of file
diff --git a/yaserde_derive/src/common/attribute.rs b/yaserde_derive/src/common/attribute.rs
index 6494844..1deb334 100644
--- a/yaserde_derive/src/common/attribute.rs
+++ b/yaserde_derive/src/common/attribute.rs
@@ -9,7 +9,7 @@ pub struct YaSerdeAttribute {
   pub default: Option<String>,
   pub default_namespace: Option<String>,
   pub flatten: bool,
-  pub namespaces: BTreeMap<String, String>,
+  pub namespaces: BTreeMap<Option<String>, String>,
   pub prefix: Option<String>,
   pub rename: Option<String>,
   pub skip_serializing_if: Option<String>,
@@ -67,10 +67,10 @@ impl YaSerdeAttribute {
                   if let Some(namespace) = get_value(&mut attr_iter) {
                     let splitted: Vec<&str> = namespace.split(": ").collect();
                     if splitted.len() == 2 {
-                      namespaces.insert(splitted[0].to_owned(), splitted[1].to_owned());
+                      namespaces.insert(Some(splitted[0].to_owned()), splitted[1].to_owned());
                     }
                     if splitted.len() == 1 {
-                      namespaces.insert("".to_owned(), splitted[0].to_owned());
+                      namespaces.insert(None, splitted[0].to_owned());
                     }
                   }
                 }
@@ -139,7 +139,7 @@ impl YaSerdeAttribute {
       .namespaces
       .iter()
       .map(|(prefix, namespace)| {
-        if configured_prefix == Some(prefix.to_string()) {
+        if configured_prefix.eq(prefix) {
           Some(quote!(#namespace => {}))
         } else {
           None
@@ -316,7 +316,7 @@ fn parse_attributes_with_values() {
   let attrs = YaSerdeAttribute::parse(&attributes);
 
   let mut namespaces = BTreeMap::new();
-  namespaces.insert("example".to_string(), "http://example.org".to_string());
+  namespaces.insert(Some("example".to_string()), "http://example.org".to_string());
 
   assert_eq!(
     YaSerdeAttribute {
diff --git a/yaserde_derive/src/ser/namespace.rs b/yaserde_derive/src/ser/namespace.rs
index 5bf69c4..9e75894 100644
--- a/yaserde_derive/src/ser/namespace.rs
+++ b/yaserde_derive/src/ser/namespace.rs
@@ -7,12 +7,10 @@ pub fn generate_namespaces_definition(attributes: &YaSerdeAttribute) -> TokenStr
     .namespaces
     .iter()
     .map(|(prefix, namespace)| {
-      if let Some(dn) = &attributes.default_namespace {
-        if dn == prefix {
+      if attributes.default_namespace.eq(prefix) {
           return Some(quote!(
             .default_ns(#namespace)
           ));
-        }
       }
       Some(quote!(
         .ns(#prefix, #namespace)