diff --git a/src/net/net.go b/src/net/net.go
index c850d2b1fd..339c972906 100644
--- a/src/net/net.go
+++ b/src/net/net.go
@@ -135,6 +135,8 @@ func (c *conn) Close() error {
 }
 
 // LocalAddr returns the local network address.
+// The Addr returned is shared by all invocations of LocalAddr, so
+// do not modify it.
 func (c *conn) LocalAddr() Addr {
 	if !c.ok() {
 		return nil
@@ -143,6 +145,8 @@ func (c *conn) LocalAddr() Addr {
 }
 
 // RemoteAddr returns the remote network address.
+// The Addr returned is shared by all invocations of RemoteAddr, so
+// do not modify it.
 func (c *conn) RemoteAddr() Addr {
 	if !c.ok() {
 		return nil
diff --git a/src/net/tcpsock_plan9.go b/src/net/tcpsock_plan9.go
index 52019d7b4e..ae2194277d 100644
--- a/src/net/tcpsock_plan9.go
+++ b/src/net/tcpsock_plan9.go
@@ -157,6 +157,8 @@ func (l *TCPListener) Close() error {
 }
 
 // Addr returns the listener's network address, a *TCPAddr.
+// The Addr returned is shared by all invocations of Addr, so
+// do not modify it.
 func (l *TCPListener) Addr() Addr { return l.fd.laddr }
 
 // SetDeadline sets the deadline associated with the listener.
diff --git a/src/net/tcpsock_posix.go b/src/net/tcpsock_posix.go
index dd78aefa77..aaff0acaa6 100644
--- a/src/net/tcpsock_posix.go
+++ b/src/net/tcpsock_posix.go
@@ -258,6 +258,8 @@ func (l *TCPListener) Close() error {
 }
 
 // Addr returns the listener's network address, a *TCPAddr.
+// The Addr returned is shared by all invocations of Addr, so
+// do not modify it.
 func (l *TCPListener) Addr() Addr { return l.fd.laddr }
 
 // SetDeadline sets the deadline associated with the listener.
diff --git a/src/net/unixsock_plan9.go b/src/net/unixsock_plan9.go
index c60c1d83bb..64a511d648 100644
--- a/src/net/unixsock_plan9.go
+++ b/src/net/unixsock_plan9.go
@@ -115,6 +115,8 @@ func (l *UnixListener) Close() error {
 }
 
 // Addr returns the listener's network address.
+// The Addr returned is shared by all invocations of Addr, so
+// do not modify it.
 func (l *UnixListener) Addr() Addr { return nil }
 
 // SetDeadline sets the deadline associated with the listener.
diff --git a/src/net/unixsock_posix.go b/src/net/unixsock_posix.go
index 3c2e78bdca..d7127d9c69 100644
--- a/src/net/unixsock_posix.go
+++ b/src/net/unixsock_posix.go
@@ -321,6 +321,8 @@ func (l *UnixListener) Close() error {
 }
 
 // Addr returns the listener's network address.
+// The Addr returned is shared by all invocations of Addr, so
+// do not modify it.
 func (l *UnixListener) Addr() Addr { return l.fd.laddr }
 
 // SetDeadline sets the deadline associated with the listener.