diff --git a/Cargo.toml b/Cargo.toml
index 050537b..db5a7d6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -24,7 +24,7 @@ optional = true
 version = "1"
 
 [dependencies.num-traits]
-version = "0.2.11"
+version = "0.2.18"
 default-features = false
 features = ["i128"]
 
diff --git a/src/lib.rs b/src/lib.rs
index 3c647e2..8716712 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -30,7 +30,7 @@ use core::str::FromStr;
 #[cfg(feature = "std")]
 use std::error::Error;
 
-use num_traits::{Inv, MulAdd, Num, One, Pow, Signed, Zero};
+use num_traits::{ConstOne, ConstZero, Inv, MulAdd, Num, One, Pow, Signed, Zero};
 
 use num_traits::float::FloatCore;
 #[cfg(any(feature = "std", feature = "libm"))]
@@ -104,7 +104,9 @@ impl<T> Complex<T> {
 }
 
 impl<T: Clone + Num> Complex<T> {
-    /// Returns imaginary unit
+    /// Returns the imaginary unit.
+    ///
+    /// See also [`Complex::I`].
     #[inline]
     pub fn i() -> Self {
         Self::new(T::zero(), T::one())
@@ -1146,6 +1148,15 @@ impl<T: Clone + Num> Rem<T> for Complex<T> {
 real_arithmetic!(usize, u8, u16, u32, u64, u128, isize, i8, i16, i32, i64, i128, f32, f64);
 
 // constants
+impl<T: ConstZero> Complex<T> {
+    /// A constant `Complex` 0.
+    pub const ZERO: Self = Self::new(T::ZERO, T::ZERO);
+}
+
+impl<T: Clone + Num + ConstZero> ConstZero for Complex<T> {
+    const ZERO: Self = Self::ZERO;
+}
+
 impl<T: Clone + Num> Zero for Complex<T> {
     #[inline]
     fn zero() -> Self {
@@ -1164,6 +1175,18 @@ impl<T: Clone + Num> Zero for Complex<T> {
     }
 }
 
+impl<T: ConstOne + ConstZero> Complex<T> {
+    /// A constant `Complex` 1.
+    pub const ONE: Self = Self::new(T::ONE, T::ZERO);
+
+    /// A constant `Complex` _i_, the imaginary unit.
+    pub const I: Self = Self::new(T::ZERO, T::ONE);
+}
+
+impl<T: Clone + Num + ConstOne + ConstZero> ConstOne for Complex<T> {
+    const ONE: Self = Self::ONE;
+}
+
 impl<T: Clone + Num> One for Complex<T> {
     #[inline]
     fn one() -> Self {