diff --git a/PScope.h b/PScope.h
index a6c11466c..d2b0feb53 100644
--- a/PScope.h
+++ b/PScope.h
@@ -83,6 +83,9 @@ class LexicalScope {
       map<perm_string,param_expr_t>parameters;
       map<perm_string,param_expr_t>localparams;
 
+	// Defined types in the scope.
+      map<perm_string,data_type_t*>typedefs;
+
 	// Named events in the scope.
       map<perm_string,PEvent*>events;
 
@@ -105,6 +108,8 @@ class LexicalScope {
       LexicalScope* parent_scope() const { return parent_; }
 
     protected:
+      void dump_typedefs_(ostream&out, unsigned indent) const;
+
       void dump_parameters_(ostream&out, unsigned indent) const;
 
       void dump_localparams_(ostream&out, unsigned indent) const;
diff --git a/lexor.lex b/lexor.lex
index a197990fb..a6a683607 100644
--- a/lexor.lex
+++ b/lexor.lex
@@ -308,6 +308,13 @@ TU [munpf]
 	    }
       }
 
+	/* If this identifer names a previously declared type, then
+	   return this as a TYPE_IDENTIFIER instead. */
+      if (rc == IDENTIFIER && gn_system_verilog()) {
+	    if (pform_test_type_identifier(yylval.text))
+		  rc = TYPE_IDENTIFIER;
+      }
+
       return rc;
   }
 
diff --git a/parse.y b/parse.y
index f337e0670..08d9ba3cd 100644
--- a/parse.y
+++ b/parse.y
@@ -347,7 +347,7 @@ static void current_task_set_statement(vector<Statement*>*s)
       list<index_component_t> *dimensions;
 };
 
-%token <text>   IDENTIFIER SYSTEM_IDENTIFIER STRING TIME_LITERAL
+%token <text>   IDENTIFIER SYSTEM_IDENTIFIER TYPE_IDENTIFIER STRING TIME_LITERAL
 %token <discipline> DISCIPLINE_IDENTIFIER
 %token <text>   PATHPULSE_IDENTIFIER
 %token <number> BASED_NUMBER DEC_NUMBER
@@ -706,10 +706,11 @@ block_item_decl
        if ($1) delete $1;
      }
 
-  /* variable declarations */
+  /* variable declarations. Note that data_type can be 0 if we are
+     recovering from an error. */
 
   | attribute_list_opt data_type register_variable_list ';'
-      { pform_set_data_type(@2, $2, $3);
+      { if ($2) pform_set_data_type(@2, $2, $3);
 	if ($1) delete $1;
       }
 
@@ -784,11 +785,18 @@ data_type
       { $$ = $1; }
   | enum_data_type
       { $$ = $1; }
+  | TYPE_IDENTIFIER
+      { yyerror(@1, "sorry: Named types not supported here");
+	$$ = 0;
+      }
   ;
 
 type_declaration
   : K_typedef data_type IDENTIFIER ';'
-      { yyerror(@1, "sorry: typedef not yet supported."); }
+      { perm_string name = lex_strings.make($3);
+	pform_set_typedef(name, $2);
+	delete[]$3;
+      }
   ;
 
   /* The structure for an enumeration data type is the keyword "enum",
diff --git a/parse_misc.h b/parse_misc.h
index f3b5dfc9b..0217a0cda 100644
--- a/parse_misc.h
+++ b/parse_misc.h
@@ -77,6 +77,14 @@ extern UCDriveType uc_drive;
 extern bool have_timeunit_decl;
 extern bool have_timeprec_decl;
 
+/*
+ * Test if this identifier is a type identifier in the current
+ * context. The pform code needs to help the lexor here because the
+ * parser detects typedefs and marks the typedef'ed identifiers as
+ * type names.
+ */
+extern bool pform_test_type_identifier(const char*txt);
+
 /*
  * Export these functions because we have to generate PENumber class
  * in pform.cc for user defparam definition from command file.
diff --git a/pform.cc b/pform.cc
index a056b5f82..97e7c8303 100644
--- a/pform.cc
+++ b/pform.cc
@@ -401,6 +401,28 @@ PWire*pform_get_make_wire_in_scope(perm_string name, NetNet::Type net_type, NetN
       return cur;
 }
 
+void pform_set_typedef(perm_string name, data_type_t*data_type)
+{
+      data_type_t*&ref = lexical_scope->typedefs[name];
+      ivl_assert(*data_type, ref == 0);
+      ref = data_type;
+}
+
+bool pform_test_type_identifier(const char*txt)
+{
+	// If there is no lexical_scope yet, then there is NO WAY the
+	// identifier can be a type_identifier.
+      if (lexical_scope == 0)
+	    return false;
+
+      perm_string name = lex_strings.make(txt);
+      map<perm_string,data_type_t*>::iterator cur = lexical_scope->typedefs.find(name);
+      if (cur != lexical_scope->typedefs.end())
+	    return true;
+      else
+	    return false;
+}
+
 static void pform_put_behavior_in_scope(PProcess*pp)
 {
       lexical_scope->behaviors.push_back(pp);
diff --git a/pform.h b/pform.h
index 56f0a4aac..dbdf85942 100644
--- a/pform.h
+++ b/pform.h
@@ -224,6 +224,8 @@ extern void pform_endgenerate();
  */
 extern PGenerate* pform_parent_generate(void);
 
+extern void pform_set_typedef(perm_string name, data_type_t*data_type);
+
 /*
  * The makewire functions announce to the pform code new wires. These
  * go into a module that is currently opened.
diff --git a/pform_dump.cc b/pform_dump.cc
index cd8829ccf..88fa71520 100644
--- a/pform_dump.cc
+++ b/pform_dump.cc
@@ -141,6 +141,11 @@ std::ostream& operator << (std::ostream&out, ivl_dis_domain_t dom)
       return out;
 }
 
+void data_type_t::pform_dump(ostream&out, unsigned indent) const
+{
+      out << setw(indent) << "" << typeid(*this).name() << endl;
+}
+
 static void dump_attributes_map(ostream&out,
 				const map<perm_string,PExpr*>&attributes,
 				int ind)
@@ -1050,6 +1055,15 @@ void PGenerate::dump(ostream&out, unsigned indent) const
       }
 }
 
+void LexicalScope::dump_typedefs_(ostream&out, unsigned indent) const
+{
+      typedef map<perm_string,data_type_t*>::const_iterator iter_t;
+      for (iter_t cur = typedefs.begin() ; cur != typedefs.end() ; ++ cur) {
+	    out << setw(indent) << "" << "typedef of " << cur->first << ":" << endl;
+	    cur->second->pform_dump(out, indent+4);
+      }
+}
+
 void LexicalScope::dump_parameters_(ostream&out, unsigned indent) const
 {
       typedef map<perm_string,param_expr_t>::const_iterator parm_iter_t;
@@ -1189,6 +1203,8 @@ void Module::dump(ostream&out) const
 	    out << ")" << endl;
       }
 
+      dump_typedefs_(out, 4);
+
       dump_parameters_(out, 4);
 
       dump_localparams_(out, 4);
diff --git a/pform_types.h b/pform_types.h
index db0739552..354353dd4 100644
--- a/pform_types.h
+++ b/pform_types.h
@@ -70,6 +70,9 @@ struct decl_assignment_t {
  */
 struct data_type_t : public LineInfo {
       virtual ~data_type_t() = 0;
+
+	// This method is used by the pform dumper to diagnostic dump.
+      virtual void pform_dump(std::ostream&out, unsigned indent) const;
 };
 
 /*