diff --git a/IP.pm b/IP.pm
index 98922be..39756b7 100644
--- a/IP.pm
+++ b/IP.pm
@@ -32,7 +32,7 @@
 );
 require Exporter;
 
-@EXPORT_OK = qw(Compact Coalesce Zero Zeros Ones V4mask V4net Exclude netlimit);
+@EXPORT_OK = qw(Compact Coalesce Zero Zeros Ones V4mask V4net Subtract Exclude netlimit);
 @EXPORT_FAIL = qw($_netlimit);
 
 @ISA = qw(Exporter NetAddr::IP::Lite);
@@ -58,6 +58,7 @@
 	Ones
 	V4mask
 	V4net
+	Subtract
 	Exclude
 	netlimit
 	:aton		DEPRECATED
@@ -422,6 +423,29 @@
   return &coalesce;
 }
 
+sub Subtract {
+  my @add = ref $_[0] eq __PACKAGE__ ? ($_[0]) : @{$_[0]};
+  my @sub = @{$_[1]};
+  my @ret;
+  while (@add && @sub) {
+    if ($sub[0]->contains($add[0])) {
+      shift @add;
+    } elsif ($add[0]->contains($sub[0])) {
+      my ($low,$up) = Exclude(shift @add,shift @sub);
+      push @ret, @$low;
+      unshift @add, @$up;
+    } else {
+      if ($add[0]->bigint < $sub[0]->bigint) {
+        push @ret, shift @add;
+      } else {
+        shift @sub;
+      }
+    }
+  }
+  push @ret, @add;
+  return \@ret;
+}
+
 sub Exclude {
   return ([],[]) if $_[0] == $_[1];
   return ([$_[0]],[]) unless $_[1]->within($_[0]);
diff --git a/t/v4-subtract.t b/t/v4-subtract.t
new file mode 100644
index 0000000..113934c
--- /dev/null
+++ b/t/v4-subtract.t
@@ -0,0 +1,86 @@
+use Test::More;
+use NetAddr::IP qw(Exclude Subtract);
+
+my @r = (
+	['10.0.0.0/8','10.0.0.0/9'],
+	['10.0.0.0/8','10.0.0.0/8'],
+	['10.0.0.0/8','10.128.0.0/9'],
+	['10.0.0.0/8','10.128.0.0/10'],
+	['10.0.0.0/8','10.0.0.0/32'],
+	['192.168.0.0/24','192.168.0.255/32'],
+	['192.168.0.0/23','192.168.0.127/32'],
+	['1.2.3.4/32','1.2.3.4/32'],
+	['0.0.0.0/0','0.0.0.0/32'],
+);
+
+plan tests => 1 + 19 * scalar @r;
+
+SKIP: {
+	my $res = Subtract([],[]);
+	is("@$res", "", "Subtract([],[]) returns an empty list");
+
+	foreach my $case (@r) {
+		my $whole = [NetAddr::IP->new($case->[0])];
+		my $part1 = [NetAddr::IP->new($case->[1])];
+		my ($low,$up) = Exclude($whole->[0],$part1->[0]);
+		my $part2 = [@{$low},@{$up}];
+		my $res = [];
+
+		$res = Subtract($whole,$part1);
+		is("@$res", "@$part2", "Subtract(@$whole,@$part1) returns @$part2");
+
+		$res = $whole->[0]->Subtract($part1);
+		is("@$res", "@$part2", "($whole->[0])->Subtract(@$part1) returns @$part2");
+
+		$res = Subtract($whole,$part2);
+		is("@$res", "@$part1", "Subtract(@$whole,@$part2) returns @$part1");
+
+		$res = $whole->[0]->Subtract($part2);
+		is("@$res", "@$part1", "($whole->[0])->Subtract(@$part2) returns @$part1");
+
+		$res = Subtract($part1,$part2);
+		is("@$res", "@$part1", "Subtract(@$part1,@$part2) returns @$part1");
+
+		$res = $part1->[0]->Subtract($part2);
+		is("@$res", "@$part1", "($part1->[0])->Subtract(@$part2) returns @$part1");
+
+		$res = Subtract($part2,$part1);
+		is("@$res", "@$part2", "Subtract(@$part2,@$part1) returns @$part2");
+
+		$res = Subtract(Subtract($whole,$part1),$part2);
+		is("@$res", "", "Subtract(Subtract(@$whole,@$part1),$part2) returns an empty list");
+
+		$res = Subtract($whole->[0]->Subtract($part1),$part2);
+		is("@$res", "", "Subtract(($whole->[0])->Subtract(@$part1),$part2) returns an empty list");
+
+		$res = Subtract(Subtract($whole,$part2),$part1);
+		is("@$res", "", "Subtract(Subtract(@$whole,@$part2),$part1) returns an empty list");
+
+		$res = Subtract($whole->[0]->Subtract($part2),$part1);
+		is("@$res", "", "Subtract(($whole->[0])->Subtract(@$part2),$part1) returns an empty list");
+
+		$res = Subtract($whole,$whole);
+		is("@$res", "", "Subtract(@$whole,@$whole) returns an empty list");
+
+		$res = $whole->[0]->Subtract($whole);
+		is("@$res", "", "($whole->[0])->Subtract(@$whole) returns an empty list");
+
+		$res = Subtract($part1,$part1);
+		is("@$res", "", "Subtract(@$part1,@$part1) returns an empty list");
+
+		$res = $part1->[0]->Subtract($part1);
+		is("@$res", "", "($part1->[0])->Subract(@$part1) returns an empty list");
+
+		$res = Subtract($part2,$part2);
+		is("@$res", "", "Subtract(@$part2,@$part2) returns an empty list");
+
+		$res = Subtract($part1,$whole);
+		is("@$res", "", "Subtract(@$part1,@$whole) returns an empty list");
+
+		$res = $part1->[0]->Subtract($whole);
+		is("@$res", "", "($part1->[0])->Subtract(@$whole) returns an empty list");
+
+		$res = Subtract($part2,$whole);
+		is("@$res", "", "Subtract(@$part2,@$whole) returns an empty list");
+	}
+}
diff --git a/t/v6-subtract.t b/t/v6-subtract.t
new file mode 100644
index 0000000..9274688
--- /dev/null
+++ b/t/v6-subtract.t
@@ -0,0 +1,82 @@
+use Test::More;
+use NetAddr::IP qw(:lower Exclude Subtract);
+
+my @r = (
+	['2001:db8::/32','2001:db8::/33'],
+	['2001:db8::/64','2001:db8::/64'],
+	['2001:db8::/128','2001:db8::/128'],
+	['2001:db8::/32','2001:db8:8000::/33'],
+	['2001:db8::/32','2001:db8:8000::/34'],
+);
+
+plan tests => 1 + 19 * scalar @r;
+
+SKIP: {
+	my $res = Subtract([],[]);
+	is("@$res", "", "Subtract([],[]) returns an empty list");
+
+	foreach my $case (@r) {
+		my $whole = [NetAddr::IP->new($case->[0])];
+		my $part1 = [NetAddr::IP->new($case->[1])];
+		my ($low,$up) = Exclude($whole->[0],$part1->[0]);
+		my $part2 = [@{$low},@{$up}];
+		my $res = [];
+
+		$res = Subtract($whole,$part1);
+		is("@$res", "@$part2", "Subtract(@$whole,@$part1) returns @$part2");
+
+		$res = $whole->[0]->Subtract($part1);
+		is("@$res", "@$part2", "($whole->[0])->Subtract(@$part1) returns @$part2");
+
+		$res = Subtract($whole,$part2);
+		is("@$res", "@$part1", "Subtract(@$whole,@$part2) returns @$part1");
+
+		$res = $whole->[0]->Subtract($part2);
+		is("@$res", "@$part1", "($whole->[0])->Subtract(@$part2) returns @$part1");
+
+		$res = Subtract($part1,$part2);
+		is("@$res", "@$part1", "Subtract(@$part1,@$part2) returns @$part1");
+
+		$res = $part1->[0]->Subtract($part2);
+		is("@$res", "@$part1", "($part1->[0])->Subtract(@$part2) returns @$part1");
+
+		$res = Subtract($part2,$part1);
+		is("@$res", "@$part2", "Subtract(@$part2,@$part1) returns @$part2");
+
+		$res = Subtract(Subtract($whole,$part1),$part2);
+		is("@$res", "", "Subtract(Subtract(@$whole,@$part1),$part2) returns an empty list");
+
+		$res = Subtract($whole->[0]->Subtract($part1),$part2);
+		is("@$res", "", "Subtract(($whole->[0])->Subtract(@$part1),$part2) returns an empty list");
+
+		$res = Subtract(Subtract($whole,$part2),$part1);
+		is("@$res", "", "Subtract(Subtract(@$whole,@$part2),$part1) returns an empty list");
+
+		$res = Subtract($whole->[0]->Subtract($part2),$part1);
+		is("@$res", "", "Subtract(($whole->[0])->Subtract(@$part2),$part1) returns an empty list");
+
+		$res = Subtract($whole,$whole);
+		is("@$res", "", "Subtract(@$whole,@$whole) returns an empty list");
+
+		$res = $whole->[0]->Subtract($whole);
+		is("@$res", "", "($whole->[0])->Subtract(@$whole) returns an empty list");
+
+		$res = Subtract($part1,$part1);
+		is("@$res", "", "Subtract(@$part1,@$part1) returns an empty list");
+
+		$res = $part1->[0]->Subtract($part1);
+		is("@$res", "", "($part1->[0])->Subract(@$part1) returns an empty list");
+
+		$res = Subtract($part2,$part2);
+		is("@$res", "", "Subtract(@$part2,@$part2) returns an empty list");
+
+		$res = Subtract($part1,$whole);
+		is("@$res", "", "Subtract(@$part1,@$whole) returns an empty list");
+
+		$res = $part1->[0]->Subtract($whole);
+		is("@$res", "", "($part1->[0])->Subtract(@$whole) returns an empty list");
+
+		$res = Subtract($part2,$whole);
+		is("@$res", "", "Subtract(@$part2,@$whole) returns an empty list");
+	}
+}