diff --git a/go/go-encode-id.cc b/go/go-encode-id.cc
index 7c7aa13..550da97 100644
--- a/go/go-encode-id.cc
+++ b/go/go-encode-id.cc
@@ -253,3 +253,16 @@
     }
   return ret;
 }
+
+// Encode a package path.
+
+std::string
+go_mangle_pkgpath(const std::string& pkgpath)
+{
+  std::string s = pkgpath;
+  for (size_t i = s.find('.');
+       i != std::string::npos;
+       i = s.find('.', i + 1))
+    s.replace(i, 1, ".x2e"); // 0x2e is the ASCII encoding for '.'
+  return s;
+}
diff --git a/go/go-encode-id.h b/go/go-encode-id.h
index 70126ba..2d09b0c 100644
--- a/go/go-encode-id.h
+++ b/go/go-encode-id.h
@@ -34,4 +34,12 @@
 extern std::string
 go_mangle_struct_tag(const std::string& tag);
 
+// Encode a package path.  A package path can contain any arbitrary
+// character, including '.'.  go_encode_id expects that any '.' will
+// be inserted by name mangling in a controlled manner.  So first
+// translate any '.' using the same .x encoding as used by
+// go_mangle_struct_tag.
+extern std::string
+go_mangle_pkgpath(const std::string& pkgpath);
+
 #endif // !defined(GO_ENCODE_ID_H)
diff --git a/go/gogo.cc b/go/gogo.cc
index a79cfc3..1ee49dc 100644
--- a/go/gogo.cc
+++ b/go/gogo.cc
@@ -298,7 +298,7 @@
 Gogo::set_pkgpath(const std::string& arg)
 {
   go_assert(!this->pkgpath_set_);
-  this->pkgpath_ = arg;
+  this->pkgpath_ = go_mangle_pkgpath(arg);
   this->pkgpath_set_ = true;
   this->pkgpath_from_option_ = true;
 }
@@ -396,7 +396,8 @@
 	{
 	  if (!this->prefix_from_option_)
 	    this->prefix_ = "go";
-	  this->pkgpath_ = this->prefix_ + '.' + package_name;
+	  this->pkgpath_ = (go_mangle_pkgpath(this->prefix_) + '.'
+			    + package_name);
 	  this->pkgpath_symbol_ = (Gogo::pkgpath_for_symbol(this->prefix_) + '.'
 				   + Gogo::pkgpath_for_symbol(package_name));
 	}