diff --git a/README b/README
index 4369080..2a4aa05 100644
--- a/README
+++ b/README
@@ -88,7 +88,9 @@ Advanced options:
   code or signal+128.  This also makes timeout to wait until the controlled
   process is terminated.  Without this option, the script returns zero.
 
-* `--memlimit-rss`, `-s` - monitor RSS (resident set size) memory limit
+* `--memlimit-rss`, `-s` - monitor RSS (resident set size) memory limit.
+Memory limits may be specified as KB (default), MB, or GB.
+E.g. 900KB, 100MB, 1.2GB
 
 More options may be read in the script itself.  More documentation will be
 added in the future releases!
@@ -108,26 +110,30 @@ EXAMPLES
 Since you already have Perl to run the script itself, the examples will
 utilize it.
 
-Basic time limiting:
+Basic CPU time limiting:
 
     ./timeout -t 2 perl -e 'while ($i<100000000) {$i++;}'
     Outputs:
     TIMEOUT 2.04 CPU
 
-Basic memory limiting (100M of virtual memory):
+Basic memory limiting (100MB of virtual memory):
 
-    ./timeout -m 1000000 perl -e 'while ($i<100000000) {$a->{$i} = $i++;}'
+    ./timeout -m 100MB perl -e 'while ($i<100000000) {$a->{$i} = $i++;}'
     Outputs:
-    MEM 8.55
+    MEM CPU 0.41 MEM 119236 KB 116 MB 0 GB MAXMEM 119236 KB 116 MB 0 GB STALE 0 MAXMEM_RSS 100432 KB 98 MB 0 GB
+    <time name="ALL">440</time>
 
-Limit both time and memory (adjust number to match the command above):
+Limit both CPU time and memory (adjust number to match the command above). Note that the decision to kill the process is based on the logical OR of the limits:
 
-    ./timeout -m 1000000 -t 9 perl -e 'while ($i<100000000) {$x->{$i} = $i++;}'
+    ./timeout -m 100mb -t 2 perl -e 'while ($i<100000000) {$i++;}'
     Outputs:
-    MEM 8.57
-    ./timeout -m 1000000 -t 8 perl -e 'while ($i<100000000) {$x->{$i} = $i++;}'
+    TIMEOUT CPU 2.05 MEM 20552 KB 20 MB 0 GB MAXMEM 20552 KB 20 MB 0 GB STALE 0 MAXMEM_RSS 1748 KB 1 MB 0 GB
+    <time name="ALL">2100</time>
+
+    ./timeout -m 100mb -t 9 perl -e 'while ($i<100000000) {$x->{$i} = $i++;}'
     Outputs:
-    TIMEOUT 8.02 CPU
+    MEM CPU 0.41 MEM 124252 KB 121 MB 0 GB MAXMEM 124252 KB 121 MB 0 GB STALE 0 MAXMEM_RSS 108616 KB 106 MB 0 GB
+    <time name="ALL">440</time>
 
 Limit time with a lot of short child processes:
 
@@ -208,6 +214,3 @@ The script was initially developed in the Institute for System Programming of
 Russian Academy of Sciences (http://ispras.ru/en/) for Linux Driver
 Verification project (http://forge.ispras.ru/projects/ldv) in 2010-2011 by
 Pavel Shved with some contributions from Alexander Strakh.
-
-
-
diff --git a/timeout b/timeout
index 7be8c90..6221cc8 100755
--- a/timeout
+++ b/timeout
@@ -23,7 +23,10 @@
 
 sub usage{ print STDERR <<usage_ends;
 Usage:
-	timeout [-t timelimit] [-m memlimit] [-x hertz] command [arguments ...]
+	timeout [-t timelimit] [-m memlimit] [-s memlimit-rss] [-x hertz] command [arguments ...]
+
+Memory limits may be specified as KB (default), MB, or GB.
+Example: timeout -memlimit 2.5GB -memlimit-rss 7800MB
 
 usage_ends
 	die;
@@ -61,8 +64,8 @@ GetOptions(
 	'detect-hangups!'=>\$kill_stale,
 	# allow-hangups is kept for backward compatibility.
 	'allow-hangups!'=>\$kill_stale,
-	'memlimit|m=i'=>\$memlimit,
-	'memlimit-rss|s=i'=>\$memlimit_rss,
+	'memlimit|m=s'=>\$memlimit,
+	'memlimit-rss|s=s'=>\$memlimit_rss,
 	'frequency|x=i'=>\$frequency,
 	'pattern|p=s'=>\$strpat,
 	'output|o=s'=>\$output,
@@ -76,6 +79,9 @@ GetOptions(
 
 @ARGV or usage;
 
+$memlimit = parse_memory_arg($memlimit);
+$memlimit_rss = parse_memory_arg($memlimit_rss);
+
 my $uinfo = get_patterns($strpat);
 
 my $uwait = int (1_000_000 / $frequency);
@@ -446,7 +452,7 @@ sub print_uinfo
 	my $reason = shift;
 	# Print generic information to STDERR
 	my $ticks = $timeinfo->{ticks_stale} || 0;
-	printf STDERR "${id_str}%s CPU %.2f MEM %d MAXMEM %d STALE %d MAXMEM_RSS %d\n", $reason, $timeinfo->{total}, $meminfo, $maxmem, ceil($ticks/$frequency), $maxmem_rss if ($reason ne 'FINISHED') || $info_on_success;
+	printf STDERR "${id_str}%s CPU %.2f MEM %d KB %d MB %d GB MAXMEM %d KB %d MB %d GB STALE %d MAXMEM_RSS %d KB %d MB %d GB\n", $reason, $timeinfo->{total}, $meminfo, $meminfo/1024, $meminfo/1024/1024, $maxmem, $maxmem/1024, $maxmem/1024/1024, ceil($ticks/$frequency), $maxmem_rss, $maxmem_rss/1024, $maxmem_rss/1024/1024 if ($reason ne 'FINISHED') || $info_on_success;
 
 	if (defined $output){
 		open(FIL,">>", $output) or die "Can't open output file: $!\n";
@@ -516,3 +522,25 @@ sub child_status_to_exit_code
 		return $child_retv >> 8;
 	}
 }
+
+# Allow memory arguments to specified as bytes, KB, MB, or GB.
+sub parse_memory_arg
+{
+	my ($mem) = @_;
+	if (defined($mem)) {
+		if ($mem =~ /^\d+$/) {
+			$mem = int($mem);
+		} elsif ($mem =~ /(^\d*\.{0,1}\d*)kb$/i) {
+			$mem = int($1);
+		} elsif ($mem =~ /(^\d*\.{0,1}\d*)mb$/i) {
+			$mem = int($1*1024);
+		} elsif ($mem =~ /(^\d*\.{0,1}\d*)gb$/i) {
+			$mem = int($1*1024*1024);
+		} else {
+			print STDERR "Error: Unrecognized memory argument: '$mem'.\n";
+			usage();
+		}
+		printf STDERR "mem : %d KB = %.1f MB = %.1f GB\n", $mem, $mem/1024., $mem/1024./1024. if $debug;
+	}
+	return $mem;
+}