diff --git a/baselib.ml b/baselib.ml
index 0c899b4..c252b9f 100644
--- a/baselib.ml
+++ b/baselib.ml
@@ -9,6 +9,7 @@ let _types_ =
        ; "%sub", Func_t (Int_t, [ Int_t; Int_t ])
        ; "%mul", Func_t (Int_t, [ Int_t; Int_t ])
        ; "%div", Func_t (Int_t, [ Int_t; Int_t ])
+       ; "%rem", Func_t (Int_t, [ Int_t; Int_t ])
        ; "%seq", Func_t (Bool_t, [ Int_t; Int_t ])
        ; "%sge", Func_t (Bool_t, [ Int_t; Int_t ])
        ; "%sgt", Func_t (Bool_t, [ Int_t; Int_t ])
@@ -30,6 +31,7 @@ let builtins =
     ; "%sub", [ Lw (T0, Mem (SP, 4)); Lw (T1, Mem (SP, 0)); Sub (V0, T0, T1) ]
     ; "%mul", [ Lw (T0, Mem (SP, 4)); Lw (T1, Mem (SP, 0)); Mul (V0, T0, T1) ]
     ; "%div", [ Lw (T0, Mem (SP, 4)); Lw (T1, Mem (SP, 0)); Div (V0, T0, T1) ]
+    ; "%rem", [ Lw (T0, Mem (SP, 4)); Lw (T1, Mem (SP, 0)); Rem (V0, T0, T1) ]
     ; "%seq", [ Lw (T0, Mem (SP, 4)); Lw (T1, Mem (SP, 0)); Seq (V0, T0, T1) ]
     ; "%sge", [ Lw (T0, Mem (SP, 4)); Lw (T1, Mem (SP, 0)); Sge (V0, T0, T1) ]
     ; "%sgt", [ Lw (T0, Mem (SP, 4)); Lw (T1, Mem (SP, 0)); Sgt (V0, T0, T1) ]
diff --git a/lexer.mll b/lexer.mll
index 83d6aba..ba048f8 100644
--- a/lexer.mll
+++ b/lexer.mll
@@ -34,6 +34,7 @@ rule token = parse
   | '-'           { Lsub }
   | '*'           { Lmul }
   | '/'           { Ldiv }
+  | '%'           { Lrem }
   | "=="          { Lseq }
   | ">="          { Lsge }
   | ">"           { Lsgt }
diff --git a/mips.ml b/mips.ml
index 67b47d5..1e4fa35 100644
--- a/mips.ml
+++ b/mips.ml
@@ -47,6 +47,7 @@ type instr =
   | Mul of reg * reg * reg
   | Sub of reg * reg * reg
   | Div of reg * reg * reg
+  | Rem of reg * reg * reg
   | Abs of reg * reg
   | Seq of reg * reg * reg
   | Sge of reg * reg * reg
@@ -132,6 +133,8 @@ let fmt_instr ?(indent = "  ") = function
     Printf.sprintf "%ssub %s, %s, %s" indent (fmt_reg rd) (fmt_reg rs) (fmt_reg rt)
   | Div (rd, rs, rt) ->
     Printf.sprintf "%sdiv %s, %s, %s" indent (fmt_reg rd) (fmt_reg rs) (fmt_reg rt)
+  | Rem (rd, rs, rt) ->
+    Printf.sprintf "%srem %s, %s, %s" indent (fmt_reg rd) (fmt_reg rs) (fmt_reg rt)
   | Abs (rd, rs) -> Printf.sprintf "%sabs %s, %s" indent (fmt_reg rd) (fmt_reg rs)
   | Seq (rd, rs, rt) ->
     Printf.sprintf "%sseq %s, %s, %s" indent (fmt_reg rd) (fmt_reg rs) (fmt_reg rt)
diff --git a/parser.mly b/parser.mly
index 8cc6858..88d30a0 100644
--- a/parser.mly
+++ b/parser.mly
@@ -11,10 +11,10 @@
 %token Lend Lassign Lsc Lreturn
 %token Lbracedeb Lbracefin
 %token Lpardeb Lparfin Lcomma
-%token Ladd Lsub Lmul Ldiv Lseq Lsge Lsgt Lsle Lslt Lsne
+%token Ladd Lsub Lmul Ldiv Lrem Lseq Lsge Lsgt Lsle Lslt Lsne
 %token Lif Lelse Lwhile
 
-%left Ladd Lsub Lmul Ldiv Lseq Lsge Lsgt Lsle Lslt Lsne
+%left Ladd Lsub Lmul Ldiv Lrem Lseq Lsge Lsgt Lsle Lslt Lsne
 
 %left Lbracedeb Lparfin Lbracefin Lreturn
 %left Ltype Lbool Lint Lvar Lstr
@@ -176,6 +176,11 @@ expr:
     Call { func = "%div" ; args = [ a ; b ] ; pos = $startpos($2) }
   }
 
+  /* e % e */
+  | a = expr ; Lrem ; b = expr {
+    Call { func = "%rem" ; args = [ a ; b ] ; pos = $startpos($2) }
+  }
+
   /* e == e */
   | a = expr ; Lseq ; b = expr {
     Call { func = "%seq" ; args = [ a ; b ] ; pos = $startpos($2) }
diff --git a/tests/10_math.test b/tests/10_math.test
index 211cd95..6f82f73 100644
--- a/tests/10_math.test
+++ b/tests/10_math.test
@@ -1,4 +1,5 @@
-void main () {
+int main () {
     int res = 13 * -100 - 20 + 8;
     res = abs(res * 2) / 2;
+    return res % 2;
 }