diff --git a/src/mpz.rs b/src/mpz.rs
index 6226744..96d2421 100644
--- a/src/mpz.rs
+++ b/src/mpz.rs
@@ -95,6 +95,7 @@ extern "C" {
     fn __gmpz_millerrabin(n: mpz_srcptr, reps: c_int) -> c_int;
     fn __gmpz_urandomb(rop: mpz_ptr, state: gmp_randstate_t, n: mp_bitcnt_t);
     fn __gmpz_urandomm(rop: mpz_ptr, state: gmp_randstate_t, n: mpz_srcptr);
+    fn __gmpz_perfect_square_p(op: mpz_srcptr) -> c_int;
 }
 
 pub struct Mpz {
@@ -450,6 +451,12 @@ impl Mpz {
     pub fn is_zero(&self) -> bool {
         self.mpz._mp_size == 0
     }
+
+    pub fn is_square(&self) -> bool {
+        unsafe {
+            __gmpz_perfect_square_p(&self.mpz) != 0
+        }
+    }
 }
 
 #[derive(Debug)]
diff --git a/src/test.rs b/src/test.rs
index 3af1382..2d06bbd 100644
--- a/src/test.rs
+++ b/src/test.rs
@@ -570,6 +570,15 @@ mod mpz {
         assert_eq!(five.sign(), Sign::Positive);
         assert_eq!(minus_five.sign(), Sign::Negative);
     }
+
+    #[test]
+    fn test_is_square() {
+        let three: Mpz = From::<i64>::from(3);
+        let four: Mpz = From::<i64>::from(4);
+
+        assert_eq!(three.is_square(), false);
+        assert_eq!(four.is_square(), true);
+    }
 }
 
 mod rand {