diff --git a/src/libstd/rt/io/net/ip.rs b/src/libstd/rt/io/net/ip.rs
index 3a93fd705436..2b572574b60b 100644
--- a/src/libstd/rt/io/net/ip.rs
+++ b/src/libstd/rt/io/net/ip.rs
@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use num::FromStrRadix;
+use to_str::ToStr;
+
 type Port = u16;
 
 #[deriving(Eq, TotalEq)]
@@ -15,3 +18,42 @@ pub enum IpAddr {
     Ipv4(u8, u8, u8, u8, Port),
     Ipv6(u16, u16, u16, u16, u16, u16, u16, u16, Port)
 }
+
+impl ToStr for IpAddr {
+    fn to_str(&self) -> ~str {
+        match *self {
+            Ipv4(a, b, c, d, p) =>
+                fmt!("%u.%u.%u.%u:%u",
+                    a as uint, b as uint, c as uint, d as uint, p as uint),
+
+            // Ipv4 Compatible address
+            Ipv6(0, 0, 0, 0, 0, 0, g, h, p) => {
+                let a = fmt!("%04x", g as uint);
+                let b = FromStrRadix::from_str_radix(a.slice(2, 4), 16).unwrap();
+                let a = FromStrRadix::from_str_radix(a.slice(0, 2), 16).unwrap();
+                let c = fmt!("%04x", h as uint);
+                let d = FromStrRadix::from_str_radix(c.slice(2, 4), 16).unwrap();
+                let c = FromStrRadix::from_str_radix(c.slice(0, 2), 16).unwrap();
+
+                fmt!("[::%u.%u.%u.%u]:%u", a, b, c, d, p as uint)
+            }
+
+            // Ipv4-Mapped address
+            Ipv6(0, 0, 0, 0, 0, 1, g, h, p) => {
+                let a = fmt!("%04x", g as uint);
+                let b = FromStrRadix::from_str_radix(a.slice(2, 4), 16).unwrap();
+                let a = FromStrRadix::from_str_radix(a.slice(0, 2), 16).unwrap();
+                let c = fmt!("%04x", h as uint);
+                let d = FromStrRadix::from_str_radix(c.slice(2, 4), 16).unwrap();
+                let c = FromStrRadix::from_str_radix(c.slice(0, 2), 16).unwrap();
+
+                fmt!("[::FFFF:%u.%u.%u.%u]:%u", a, b, c, d, p as uint)
+            }
+
+            Ipv6(a, b, c, d, e, f, g, h, p) =>
+                fmt!("[%x:%x:%x:%x:%x:%x:%x:%x]:%u",
+                    a as uint, b as uint, c as uint, d as uint,
+                    e as uint, f as uint, g as uint, h as uint, p as uint)
+        }
+    }
+}