diff --git a/ast.ml b/ast.ml
index 08d1961..9a5ca57 100644
--- a/ast.ml
+++ b/ast.ml
@@ -1,8 +1,13 @@
-type type_t = Int_t
+type type_t =
+  | Int_t
+  | Bool_t
 
 module Syntax = struct
   type ident = string
-  type value = Int of int
+
+  type value =
+    | Int of int
+    | Bool of bool
 
   type expr =
     | Val of
@@ -31,7 +36,10 @@ end
 
 module IR = struct
   type ident = string
-  type value = Int of int
+
+  type value =
+    | Int of int
+    | Bool of bool
 
   type expr =
     | Val of value
diff --git a/compiler.ml b/compiler.ml
index 3257b02..f669e5c 100644
--- a/compiler.ml
+++ b/compiler.ml
@@ -10,6 +10,7 @@ type info =
 
 let compile_value = function
   | Int n -> [ Li (V0, n) ]
+  | Bool b -> [ Li (V0, if b then 1 else 0) ]
 ;;
 
 let compile_expr env = function
diff --git a/lexer.mll b/lexer.mll
index 1109e00..52c1d14 100644
--- a/lexer.mll
+++ b/lexer.mll
@@ -7,6 +7,7 @@
 
 let alpha = ['a'-'z' 'A'-'Z']
 let num   = ['0'-'9']
+let bool  = "true" | "false"
 let ident = alpha (alpha | num | '-' | '_')*
 
 rule token = parse
@@ -15,6 +16,8 @@ rule token = parse
 | '\n'          { Lexing.new_line lexbuf; token lexbuf }
 | num+ as n     { Lint (int_of_string n) }
 | "int"         { Ltype (Int_t) }
+| "bool"        { Ltype (Bool_t) }
+| bool as b     { Lbool (bool_of_string b) }
 | '='           { Lassign }
 | ';'           { Lsc }
 | ident as i    { Lvar i }
diff --git a/parser.mly b/parser.mly
index c6f0714..5f5f7b1 100644
--- a/parser.mly
+++ b/parser.mly
@@ -4,6 +4,7 @@
 %}
 
 %token <int> Lint
+%token <bool> Lbool
 
 %token <Ast.type_t> Ltype
 
@@ -38,6 +39,9 @@ expr:
   | n = Lint {
     Val { value = Int (n) ; pos = $startpos(n) }
   }
+  | b = Lbool {
+    Val { value = Bool (b) ; pos = $startpos(b) }
+  }
   | v = Lvar {
     Var { name = v ; pos = $startpos(v) }
   }
diff --git a/semantics.ml b/semantics.ml
index 63652c2..71c903f 100644
--- a/semantics.ml
+++ b/semantics.ml
@@ -9,11 +9,12 @@ exception Error of string * Lexing.position
 let errt expected given pos =
   let str_of_type_t = function
     | Int_t -> "int"
+    | Bool_t -> "bool"
   in
   raise
     (Error
        ( Printf.sprintf
-           "Expected %s but %s given."
+           "Expected %s but given %s"
            (str_of_type_t expected)
            (str_of_type_t given)
        , pos ))
@@ -31,6 +32,7 @@ let warn msg (pos : Lexing.position) =
 
 let analyze_value = function
   | Syntax.Int n -> Int n, Int_t
+  | Syntax.Bool b -> Bool b, Bool_t
 ;;
 
 let analyze_expr env ua x = function
@@ -68,6 +70,7 @@ let analyze parsed = analyze_block _types_ [] parsed
 let emit oc ast =
   let rec fmt_v = function
     | Int n -> "Int " ^ string_of_int n
+    | Bool b -> "Bool " ^ string_of_bool b
   and fmt_e = function
     | Val v -> "Val (" ^ fmt_v v ^ ")"
     | Var v -> "Var \"" ^ v ^ "\""