diff --git a/src/lib.rs b/src/lib.rs
index e53e6dd..0b4b5ef 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -42,6 +42,8 @@ use tokio_io::{IoStream, AsyncRead, AsyncWrite};
 
 mod frame;
 pub use frame::{UnixDatagramFramed, UnixDatagramCodec};
+mod ucred;
+pub use ucred::UCred;
 
 fn would_block() -> io::Error {
     io::Error::new(io::ErrorKind::WouldBlock, "would block")
@@ -250,6 +252,7 @@ impl UnixStream {
         let (a, b) = try!(mio_uds::UnixStream::pair());
         let a = try!(UnixStream::new(a, handle));
         let b = try!(UnixStream::new(b, handle));
+
         Ok((a, b))
     }
 
@@ -279,6 +282,11 @@ impl UnixStream {
         self.io.get_ref().peer_addr()
     }
 
+    /// Returns effective credentials of the process which called `connect` or `socketpair`.
+    pub fn peer_cred(&self) -> io::Result<UCred> {
+        ucred::get_peer_cred(self)
+    }
+
     /// Returns the value of the `SO_ERROR` option.
     pub fn take_error(&self) -> io::Result<Option<io::Error>> {
         self.io.get_ref().take_error()
diff --git a/src/ucred.rs b/src/ucred.rs
new file mode 100644
index 0000000..646fe73
--- /dev/null
+++ b/src/ucred.rs
@@ -0,0 +1,101 @@
+use libc::{uid_t, gid_t};
+
+/// Credentials of a process
+#[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
+pub struct UCred {
+    /// UID (user ID) of the process
+    pub uid: uid_t,
+    /// GID (group ID) of the process
+    pub gid: gid_t,
+}
+
+#[cfg(target_os = "linux")]
+pub use self::impl_linux::get_peer_cred;
+
+#[cfg(target_os = "macos")]
+pub use self::impl_macos::get_peer_cred;
+
+#[cfg(target_os = "linux")]
+pub mod impl_linux {
+    use libc::{getsockopt, SOL_SOCKET, SO_PEERCRED, c_void};
+    use std::{io, mem};
+    use UnixStream;
+    use std::os::unix::io::AsRawFd;
+
+    use libc::ucred;
+
+    pub fn get_peer_cred(sock: &UnixStream) -> io::Result<super::UCred> {
+        unsafe {
+            let raw_fd = sock.as_raw_fd();
+
+            let mut ucred = ucred { pid: 0, uid: 0, gid: 0 };
+
+            let ucred_size = mem::size_of::<ucred>();
+
+            // These paranoid checks should be optimized-out
+            assert!(mem::size_of::<u32>() <= mem::size_of::<usize>());
+            assert!(ucred_size <= u32::max_value() as usize);
+
+            let mut ucred_size = ucred_size as u32;
+            
+            let ret = getsockopt(raw_fd, SOL_SOCKET, SO_PEERCRED, &mut ucred as *mut ucred as *mut c_void, &mut ucred_size);
+            if ret == 0 && ucred_size as usize == mem::size_of::<ucred>() {
+                Ok(super::UCred {
+                    uid: ucred.uid,
+                    gid: ucred.gid,
+                })
+            } else {
+                Err(io::Error::last_os_error())
+            }
+        }
+    }
+}
+
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "freebsd"))]
+pub mod impl_macos {
+    use libc::getpeereid;
+    use std::{io, mem};
+    use UnixStream;
+    use std::os::unix::io::AsRawFd;
+
+    pub fn get_peer_cred(sock: &UnixStream) -> io::Result<super::UCred> {
+        unsafe {
+            let raw_fd = sock.as_raw_fd();
+
+            let mut cred: super::UCred = mem::uninitialized();
+
+            let ret = getpeereid(raw_fd, &mut cred.uid, &mut cred.gid);
+
+            if ret == 0 {
+                Ok(cred)
+            } else {
+                Err(io::Error::last_os_error())
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use tokio_core::reactor::Core;
+    use UnixStream;
+    use libc::geteuid;
+    use libc::getegid;
+
+    #[test]
+    fn test_socket_pair() {
+        let core = Core::new().unwrap();
+        let handle = core.handle();
+
+        let (a, b) = UnixStream::pair(&handle).unwrap();
+        let cred_a = a.peer_cred().unwrap();
+        let cred_b = b.peer_cred().unwrap();
+        assert_eq!(cred_a, cred_b);
+
+        let uid = unsafe { geteuid() };
+        let gid = unsafe { getegid() };
+
+        assert_eq!(cred_a.uid, uid);
+        assert_eq!(cred_a.gid, gid);
+    }
+}