diff --git a/extensions/checks/wmi_metrics.rb b/extensions/checks/wmi_metrics.rb
new file mode 100644
index 000000000..e53dc30dd
--- /dev/null
+++ b/extensions/checks/wmi_metrics.rb
@@ -0,0 +1,190 @@
+# WMI Metrics
+# ===
+#
+# Collects a variety of system metrics every 10 seconds (by default).
+# Expects a "graphite" handler on the Sensu server, eg:
+#
+# "graphite": {
+#   "type": "tcp",
+#   "socket": {
+#     "host": "graphite.hw-ops.com",
+#     "port": 2003
+#   },
+#   "mutator": "only_check_output"
+# }
+#
+# Copyright 2014 Heavy Water Operations, LLC.
+#
+# Released under the same terms as Sensu (the MIT license); see LICENSE
+# for details.
+
+require 'ruby-wmi'
+
+module Sensu
+  module Extension
+    class WMIMetrics < Check
+      def name
+        'wmi_metrics'
+      end
+
+      def description
+        'collects system metrics, using WMI and the graphite plain-text format'
+      end
+
+      def definition
+        {
+          :type => 'metric',
+          :name => name,
+          :interval => options[:interval],
+          :standalone => true,
+          :handler => options[:handler]
+        }
+      end
+
+      def post_init
+        @metrics = []
+      end
+
+      def run
+        memory_metrics do
+          disk_metrics do
+            cpu_metrics do
+              network_interface_metrics do
+                yield flush_metrics, 0
+              end
+            end
+          end
+        end
+      end
+
+      private
+
+      def options
+        return @options if @options
+        @options = {
+          :interval => 10,
+          :handler => 'graphite',
+          :add_client_prefix => true,
+          :path_prefix => 'WMI'
+        }
+        if settings[:system_profile].is_a?(Hash)
+          @options.merge!(settings[:system_profile])
+        end
+        @options
+      end
+
+      def flush_metrics
+        metrics = @metrics.join("\n") + "\n"
+        @metrics = []
+        metrics
+      end
+
+      def add_metric(*args)
+        value = args.pop
+        path = []
+        if options[:add_client_prefix]
+          path << settings[:client][:name]
+        end
+        path << options[:path_prefix]
+        path = (path + args).join('.')
+        @metrics << [path, value, Time.now.to_i].join(' ')
+      end
+
+      def formatted_perf_data(provider, filter=:first)
+        full_provider = 'Win32_PerfFormattedData_' + provider
+        query = Proc.new do
+          begin
+            ::WMI.const_get(full_provider).find(filter)
+          rescue => error
+            @logger.error('WMI query error', {
+              :error => error.to_s
+            })
+            nil
+          end
+        end
+        EM::defer(query, Proc.new { |data| yield data })
+      end
+
+      def memory_metrics
+        formatted_perf_data('PerfOS_Memory') do |data|
+          unless data.nil?
+            %w[
+              AvailableBytes
+              CacheBytes
+              CommittedBytes
+            ].each do |point|
+              add_metric('Memory', point, data.send(point.to_sym))
+            end
+          end
+          yield
+        end
+      end
+
+      def disk_metrics
+        formatted_perf_data('PerfDisk_LogicalDisk', :all) do |disks|
+          unless disks.nil?
+            disks.each do |data|
+              %w[
+                AvgDiskQueueLength
+                FreeMegabytes
+                PercentDiskTime
+                PercentFreeSpace
+              ].each do |point|
+                disk_name = data.Name.gsub(/[^0-9a-z]/i, '')
+                add_metric('Disk', disk_name, point, data.send(point.to_sym))
+              end
+            end
+          end
+          yield
+        end
+      end
+
+      def cpu_metrics
+        formatted_perf_data('PerfOS_Processor', :all) do |processors|
+          unless processors.nil?
+            processors.each do |data|
+              %w[
+                InterruptsPerSec
+                PercentIdleTime
+                PercentInterruptTime
+                PercentPrivilegedTime
+                PercentProcessorTime
+                PercentUserTime
+              ].each do |point|
+                cpu_name = data.Name.gsub(/[^0-9a-z]/i, '')
+                add_metric('CPU', cpu_name, point, data.send(point.to_sym))
+              end
+            end
+          end
+          yield
+        end
+      end
+
+      def network_interface_metrics
+        formatted_perf_data('Tcpip_NetworkInterface', :all) do |interfaces|
+          unless interfaces.nil?
+            interfaces.each do |data|
+              %w[
+                BytesReceivedPerSec
+                BytesSentPerSec
+                BytesTotalPerSec
+                OutputQueueLength
+                PacketsOutboundDiscarded
+                PacketsOutboundErrors
+                PacketsPerSec
+                PacketsReceivedDiscarded
+                PacketsReceivedErrors
+                PacketsReceivedPerSec
+                PacketsSentPerSec
+              ].each do |point|
+                interface_name = data.Name.gsub(/[^0-9a-z]/i, '')
+                add_metric('Interface', interface_name, point, data.send(point.to_sym))
+              end
+            end
+          end
+          yield
+        end
+      end
+    end
+  end
+end