diff --git a/java/src/org/broadinstitute/sting/playground/gatk/walkers/FlagStatReadWalker.java b/java/src/org/broadinstitute/sting/playground/gatk/walkers/FlagStatReadWalker.java
new file mode 100644
index 000000000..03fe72bbc
--- /dev/null
+++ b/java/src/org/broadinstitute/sting/playground/gatk/walkers/FlagStatReadWalker.java
@@ -0,0 +1,179 @@
+package org.broadinstitute.sting.playground.gatk.walkers;
+
+import net.sf.samtools.SAMRecord;
+
+import java.text.DecimalFormat;
+import java.text.NumberFormat;
+
+import org.broadinstitute.sting.gatk.walkers.ReadWalker;
+
+
+/*
+ * Copyright (c) 2009 The Broad Institute
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * @author aaron
+ *         <p/>
+ *         Class FlagStatReadWalker
+ *         <p/>
+ *         This walker mirrors that stats that are generated by the flagstat
+ *         command of samtools.
+ */
+public class FlagStatReadWalker extends ReadWalker<Integer, Integer> {
+
+
+    // what comes out of the flagstat
+    class FlagStat {
+        int readCount = 0;
+        int QC_failure = 0;
+        int duplicates = 0;
+        int mapped = 0;
+        int paired_in_sequencing = 0;
+        int read1 = 0;
+        int read2 = 0;
+        int properly_paired = 0;
+        int with_itself_and_mate_mapped = 0;
+        int singletons = 0;
+        int with_mate_mapped_to_a_different_chr = 0;
+        int with_mate_mapped_to_a_different_chr_maq_greaterequal_than_5 = 0;
+
+        public String toString() {
+            String ret = "";
+            StringBuilder builder = new StringBuilder(ret);
+            NumberFormat percentFormatter = new DecimalFormat("#0.00");
+            builder.append(readCount);
+            builder.append(" in total\n");
+
+            builder.append(QC_failure);
+            builder.append(" QC failure\n");
+
+
+            builder.append(duplicates);
+            builder.append(" duplicates\n");
+
+            builder.append(mapped);
+            builder.append(" mapped (");
+            builder.append(percentFormatter.format(( (float)mapped / (float)readCount ) * 100.0));
+            builder.append("%)\n");
+
+            builder.append(paired_in_sequencing);
+            builder.append(" paired in sequencing\n");
+
+
+            builder.append(read1);
+            builder.append(" read1\n");
+
+            builder.append(read2);
+            builder.append(" read2\n");
+
+            builder.append(properly_paired);
+            builder.append(" properly paired (");
+            builder.append(percentFormatter.format(( (float)properly_paired / (float)readCount ) * 100.0));
+            builder.append("%)\n");
+
+
+            builder.append(with_itself_and_mate_mapped);
+            builder.append(" with itself and mate mapped\n");
+
+            builder.append(singletons);
+            builder.append(" singletons (");
+            builder.append(percentFormatter.format(( (float)singletons / (float)readCount ) * 100.0));
+                        builder.append("%)\n");
+
+
+            builder.append(with_mate_mapped_to_a_different_chr);
+            builder.append(" with mate mapped to a different chr\n");
+
+            builder.append(with_mate_mapped_to_a_different_chr_maq_greaterequal_than_5);
+            builder.append(" with mate mapped to a different chr (mapQ>=5)");
+
+            return builder.toString();
+        }
+
+    }
+
+
+    private FlagStat myStat = new FlagStat();
+
+    public Integer map( char[] ref, SAMRecord read ) {
+        myStat.readCount++;
+        if (read.getReadFailsVendorQualityCheckFlag()) {
+            myStat.QC_failure++;
+        }
+        if (read.getDuplicateReadFlag()) {
+            myStat.duplicates++;
+        }
+        if (read.getReferenceIndex() >= 0) {
+            myStat.mapped++;
+        }
+        if (read.getReadPairedFlag()) {
+            myStat.paired_in_sequencing++;
+
+            if (read.getSecondOfPairFlag()) {
+                myStat.read2++;
+            } else if (read.getReadPairedFlag()) {
+                myStat.read1++;
+            }
+            if (read.getProperPairFlag()) {
+
+                myStat.properly_paired++;
+            }
+            if (!read.getMateUnmappedFlag() && read.getReferenceIndex() >= 0) {
+                myStat.with_itself_and_mate_mapped++;
+            }
+            if (read.getMateUnmappedFlag()) {
+                myStat.singletons++;
+            }
+        }
+        if (read.getReferenceIndex() >= 0 && read.getMateReferenceIndex() >= 0 && read.getReferenceIndex() != read.getMateReferenceIndex()) {
+            myStat.with_mate_mapped_to_a_different_chr++;
+
+            if (read.getMappingQuality() >= 5) {
+                myStat.with_mate_mapped_to_a_different_chr_maq_greaterequal_than_5++;
+            }
+        }
+        return 1;
+
+    }
+
+    public Integer reduceInit
+            () {
+        return 0;
+    }
+
+    public Integer reduce
+            ( Integer
+                    value, Integer
+                    sum ) {
+        return value + sum;
+    }
+
+    public void onTraversalDone
+            ( Integer
+                    result ) {
+        //out.println("[REDUCE RESULT] Traversal result is: " + result);
+        out.println(myStat.toString());
+    }
+}
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