diff --git a/protected/java/src/org/broadinstitute/sting/gatk/walkers/diagnostics/diagnosetargets/DiagnoseTargets.java b/protected/java/src/org/broadinstitute/sting/gatk/walkers/diagnostics/diagnosetargets/DiagnoseTargets.java
index bde324e3c..fbf4b23c6 100644
--- a/protected/java/src/org/broadinstitute/sting/gatk/walkers/diagnostics/diagnosetargets/DiagnoseTargets.java
+++ b/protected/java/src/org/broadinstitute/sting/gatk/walkers/diagnostics/diagnosetargets/DiagnoseTargets.java
@@ -89,7 +89,12 @@ import java.util.*;
  * <p/>
  * <h3>Output</h3>
  * <p>
- * A modified VCF detailing each interval by sample
+ * A modified VCF detailing each interval by sample and information for each interval according to the thresholds used.
+ * Interval information includes GC Content, average interval depth, callable status among others.
+ *
+ * If you use the --missing option, you can get as a second output a intervals file with the loci that have missing data.
+ * This file can then be used as input to QualifyMissingIntervals for full qualification and interpretation of why
+ * the data is missing.
  * </p>
  * <p/>
  * <h3>Examples</h3>
@@ -117,6 +122,7 @@ public class DiagnoseTargets extends LocusWalker<Long, Long> {
     private static final String AVG_INTERVAL_DP_KEY = "IDP";
     private static final String LOW_COVERAGE_LOCI = "LL";
     private static final String ZERO_COVERAGE_LOCI = "ZL";
+    private static final String GC_CONTENT_KEY = "GC";
 
 
     @Output(doc = "File to which interval statistics should be written")
@@ -161,7 +167,7 @@ public class DiagnoseTargets extends LocusWalker<Long, Long> {
 
         // at this point, all intervals in intervalMap overlap with this locus, so update all of them
         for (IntervalStratification intervalStratification : intervalMap.values())
-            intervalStratification.addLocus(context);
+            intervalStratification.addLocus(context, ref);
 
         return 1L;
     }
@@ -276,6 +282,7 @@ public class DiagnoseTargets extends LocusWalker<Long, Long> {
 
         attributes.put(VCFConstants.END_KEY, interval.getStop());
         attributes.put(AVG_INTERVAL_DP_KEY, stats.averageCoverage(interval.size()));
+        attributes.put(GC_CONTENT_KEY, stats.gcContent());
 
         vcb = vcb.attributes(attributes);
         vcb = vcb.genotypes(genotypes);
@@ -391,6 +398,7 @@ public class DiagnoseTargets extends LocusWalker<Long, Long> {
         // INFO fields for overall data
         headerLines.add(VCFStandardHeaderLines.getInfoLine(VCFConstants.END_KEY));
         headerLines.add(new VCFInfoHeaderLine(AVG_INTERVAL_DP_KEY, 1, VCFHeaderLineType.Float, "Average depth across the interval. Sum of the depth in a loci divided by interval size."));
+        headerLines.add(new VCFInfoHeaderLine(GC_CONTENT_KEY, 1, VCFHeaderLineType.Float, "GC Content of the interval"));
         headerLines.add(new VCFInfoHeaderLine("Diagnose Targets", 0, VCFHeaderLineType.Flag, "DiagnoseTargets mode"));
 
         // FORMAT fields for each genotype
diff --git a/protected/java/src/org/broadinstitute/sting/gatk/walkers/diagnostics/diagnosetargets/IntervalStratification.java b/protected/java/src/org/broadinstitute/sting/gatk/walkers/diagnostics/diagnosetargets/IntervalStratification.java
index 3b5a23d51..cd38d28c6 100644
--- a/protected/java/src/org/broadinstitute/sting/gatk/walkers/diagnostics/diagnosetargets/IntervalStratification.java
+++ b/protected/java/src/org/broadinstitute/sting/gatk/walkers/diagnostics/diagnosetargets/IntervalStratification.java
@@ -47,6 +47,7 @@
 package org.broadinstitute.sting.gatk.walkers.diagnostics.diagnosetargets;
 
 import org.broadinstitute.sting.gatk.contexts.AlignmentContext;
+import org.broadinstitute.sting.gatk.contexts.ReferenceContext;
 import org.broadinstitute.sting.utils.GenomeLoc;
 import org.broadinstitute.sting.utils.exceptions.ReviewedStingException;
 import org.broadinstitute.sting.utils.pileup.ReadBackedPileup;
@@ -57,9 +58,13 @@ final class IntervalStratification extends AbstractStratification {
     private final Map<String, AbstractStratification> samples;
     private final GenomeLoc interval;
     private List<CallableStatus> callableStatuses;
+    private long gcCount = 0;
 
     public IntervalStratification(Set<String> samples, GenomeLoc interval, ThresHolder thresholds) {
         super(thresholds);
+
+        assert interval != null && interval.size() > 0;  // contracts
+
         this.interval = interval;
         this.samples = new HashMap<String, AbstractStratification>(samples.size());
         for (String sample : samples)
@@ -83,8 +88,11 @@ final class IntervalStratification extends AbstractStratification {
      * This takes the input and manages passing the data to the SampleStatistics and Locus Statistics
      *
      * @param context    The alignment context given from the walker
+     * @param ref        The reference context given from the walker
      */
-    public void addLocus(AlignmentContext context) {
+    public void addLocus(final AlignmentContext context,  final ReferenceContext ref) {
+        assert ref != null;  // contracts
+
         ReadBackedPileup pileup = context.getBasePileup();
 
         Map<String, ReadBackedPileup> samplePileups = pileup.getPileupsForSamples(samples.keySet());
@@ -99,7 +107,11 @@ final class IntervalStratification extends AbstractStratification {
 
             sampleStratification.addLocus(context.getLocation(), samplePileup);
         }
+        gcCount += (ref.getBase() == 'G' || ref.getBase() == 'C') ? 1 : 0;
+    }
 
+    public double gcContent() {
+        return (double) gcCount / interval.size();
     }
 
     /**
diff --git a/protected/java/test/org/broadinstitute/sting/gatk/walkers/diagnostics/diagnosetargets/DiagnoseTargetsIntegrationTest.java b/protected/java/test/org/broadinstitute/sting/gatk/walkers/diagnostics/diagnosetargets/DiagnoseTargetsIntegrationTest.java
index 52e385957..0259e9685 100644
--- a/protected/java/test/org/broadinstitute/sting/gatk/walkers/diagnostics/diagnosetargets/DiagnoseTargetsIntegrationTest.java
+++ b/protected/java/test/org/broadinstitute/sting/gatk/walkers/diagnostics/diagnosetargets/DiagnoseTargetsIntegrationTest.java
@@ -66,11 +66,11 @@ public class DiagnoseTargetsIntegrationTest extends WalkerTest {
 
     @Test(enabled = true)
     public void testSingleSample() {
-        DTTest("testSingleSample ", "-I " + singleSample + " -max 75", "1771e95aed2b3b240dc353f84e19847d");
+        DTTest("testSingleSample ", "-I " + singleSample + " -max 75", "6ca3d3917a7b65eaa877aa3658d80912");
     }
 
     @Test(enabled = true)
     public void testMultiSample() {
-        DTTest("testMultiSample ", "-I " + multiSample, "c7f1691dbe5f121c4a79be823d3057e5");
+        DTTest("testMultiSample ", "-I " + multiSample, "f50c6b9bef9f63f0a8b32ae9a9bdd51a");
     }
 }