diff --git a/instant-xml-macros/src/meta.rs b/instant-xml-macros/src/meta.rs
index ceb48d1..d0dadf1 100644
--- a/instant-xml-macros/src/meta.rs
+++ b/instant-xml-macros/src/meta.rs
@@ -134,7 +134,9 @@ impl NamespaceMeta {
                 (NsState::Prefix, TokenTree::Ident(id)) => NsState::Eq {
                     prefix: id.to_string(),
                 },
-                (NsState::Eq { mut prefix }, TokenTree::Punct(punct)) if punct.as_char() == '-' => {
+                (NsState::Eq { mut prefix }, TokenTree::Punct(punct))
+                    if punct.as_char() == '-' || punct.as_char() == '.' =>
+                {
                     prefix.push(punct.as_char());
                     NsState::Eq { prefix }
                 }
diff --git a/instant-xml/tests/de-ns.rs b/instant-xml/tests/de-ns.rs
index 2310b6c..a49ecf5 100644
--- a/instant-xml/tests/de-ns.rs
+++ b/instant-xml/tests/de-ns.rs
@@ -160,7 +160,7 @@ fn other_namespaces() {
 }
 
 #[derive(Debug, Eq, PartialEq, FromXml)]
-#[xml(ns("URI", dashed-ns = "dashed"))]
+#[xml(ns("URI", da_sh.ed-ns = "dashed"))]
 struct DashedNs {
     #[xml(ns("dashed"))]
     element: String,
@@ -169,7 +169,7 @@ struct DashedNs {
 #[test]
 fn dashed_ns() {
     assert_eq!(
-        from_str("<DashedNs xmlns=\"URI\" xmlns:dashed-ns=\"dashed\"><dashed-ns:element>hello</dashed-ns:element></DashedNs>"),
+        from_str("<DashedNs xmlns=\"URI\" xmlns:da_sh.ed-ns=\"dashed\"><da_sh.ed-ns:element>hello</da_sh.ed-ns:element></DashedNs>"),
         Ok(DashedNs { element: "hello".to_owned() })
     );
 }