diff --git a/include/picrin/value.h b/include/picrin/value.h
index c2029fb2..56aa9453 100644
--- a/include/picrin/value.h
+++ b/include/picrin/value.h
@@ -93,7 +93,8 @@ enum pic_tt {
   PIC_TT_SENV,
   PIC_TT_SYNTAX,
   PIC_TT_SC,
-  PIC_TT_LIB
+  PIC_TT_LIB,
+  PIC_TT_VAR
 };
 
 #define PIC_OBJECT_HEADER			\
diff --git a/src/codegen.c b/src/codegen.c
index 05ab6246..464daa8e 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -673,7 +673,8 @@ codegen(codegen_state *state, pic_value obj, bool tailpos)
   case PIC_TT_SENV:
   case PIC_TT_SYNTAX:
   case PIC_TT_SC:
-  case PIC_TT_LIB: {
+  case PIC_TT_LIB:
+  case PIC_TT_VAR: {
     pic_error(pic, "invalid expression given");
   }
   }
diff --git a/src/gc.c b/src/gc.c
index 422c527d..925ca161 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -10,6 +10,7 @@
 #include "picrin/error.h"
 #include "picrin/macro.h"
 #include "picrin/lib.h"
+#include "picrin/var.h"
 #include "xhash/xhash.h"
 
 #if GC_DEBUG
@@ -403,6 +404,14 @@ gc_mark_object(pic_state *pic, struct pic_object *obj)
     gc_mark_object(pic, (struct pic_object *)lib->senv);
     break;
   }
+  case PIC_TT_VAR: {
+    struct pic_var *var = (struct pic_var *)obj;
+    gc_mark(pic, var->value);
+    if (var->conv) {
+      gc_mark_object(pic, (struct pic_object *)var->conv);
+    }
+    break;
+  }
   case PIC_TT_NIL:
   case PIC_TT_BOOL:
   case PIC_TT_FLOAT:
@@ -539,6 +548,9 @@ gc_finalize_object(pic_state *pic, struct pic_object *obj)
     xh_destory(lib->exports);
     break;
   }
+  case PIC_TT_VAR: {
+    break;
+  }
   case PIC_TT_NIL:
   case PIC_TT_BOOL:
   case PIC_TT_FLOAT:
diff --git a/src/init.c b/src/init.c
index b1ef3b08..cf9d7ab0 100644
--- a/src/init.c
+++ b/src/init.c
@@ -22,6 +22,7 @@ void pic_init_char(pic_state *);
 void pic_init_error(pic_state *);
 void pic_init_str(pic_state *);
 void pic_init_macro(pic_state *);
+void pic_init_var(pic_state *);
 
 void
 pic_load_stdlib(pic_state *pic)
@@ -124,6 +125,7 @@ pic_init_core(pic_state *pic)
   pic_init_error(pic); DONE;
   pic_init_str(pic); DONE;
   pic_init_macro(pic); DONE;
+  pic_init_var(pic); DONE;
 
   pic_load_stdlib(pic); DONE;
 
diff --git a/src/macro.c b/src/macro.c
index 56288401..0cd38949 100644
--- a/src/macro.c
+++ b/src/macro.c
@@ -560,6 +560,7 @@ macroexpand(pic_state *pic, pic_value expr, struct pic_senv *senv)
   case PIC_TT_SENV:
   case PIC_TT_SYNTAX:
   case PIC_TT_LIB:
+  case PIC_TT_VAR:
     pic_error(pic, "unexpected value type");
     return pic_undef_value();	/* unreachable */
   }
diff --git a/src/port.c b/src/port.c
index a106350e..a1e84e3e 100644
--- a/src/port.c
+++ b/src/port.c
@@ -112,6 +112,9 @@ write(pic_state *pic, pic_value obj)
   case PIC_TT_LIB:
     printf("#<library %p>", pic_ptr(obj));
     break;
+  case PIC_TT_VAR:
+    printf("#<var %p>", pic_ptr(obj));
+    break;
   }
 }
 
diff --git a/src/value.c b/src/value.c
index b33c6fe4..2b73c53e 100644
--- a/src/value.c
+++ b/src/value.c
@@ -78,6 +78,8 @@ pic_type_repr(enum pic_tt tt)
     return "syntax";
   case PIC_TT_LIB:
     return "lib";
+  case PIC_TT_VAR:
+    return "var";
   }
   /* logic flaw */
   abort();