diff --git a/opennlp-tools/src/main/java/opennlp/tools/doccat/NGramFeatureGenerator.java b/opennlp-tools/src/main/java/opennlp/tools/doccat/NGramFeatureGenerator.java
index 1c9441113..76bbaf8f3 100644
--- a/opennlp-tools/src/main/java/opennlp/tools/doccat/NGramFeatureGenerator.java
+++ b/opennlp-tools/src/main/java/opennlp/tools/doccat/NGramFeatureGenerator.java
@@ -17,6 +17,8 @@
 
 package opennlp.tools.doccat;
 
+import opennlp.tools.util.InvalidFormatException;
+
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -27,12 +29,48 @@
  */
 public class NGramFeatureGenerator implements FeatureGenerator {
 
+  //default values for bigrams
+  private int minGram = 2;
+  private int maxGram = 2;
+
+  public NGramFeatureGenerator() {
+  }
+
+  public NGramFeatureGenerator(int minGram, int maxGram) throws InvalidFormatException {
+    if (minGram > 0 && maxGram > 0) {
+      if (minGram <= maxGram) {
+        this.minGram = minGram;
+        this.maxGram = maxGram;
+      } else {
+        throw new InvalidFormatException("Minimum range value (minGram) should be less than or equal to maximum range value (maxGram)!");
+      }
+    } else {
+      throw new InvalidFormatException("Both minimum range value (minGram) & maximum range value (maxGram) should be greater than or equal to 1!");
+    }
+  }
+
+  /**
+   * Extract N-Grams from the given text fragments according to the N-Gram range,
+   * i.e. a,b,c,d with minGram = 2 & maxGram = 3 then features would be a:b, a:b:c, b:c, b:c:d, c:d
+   * i.e. a,b,c,d with minGram = 2 & maxGram = 2 then features would be a:b, b:c, c:d
+   *
+   * @param text      the text fragments to extract features from
+   * @param extraInfo optional extra information to be used by the feature generator
+   * @return a collection of features
+   */
   public Collection<String> extractFeatures(String[] text, Map<String, Object> extraInfo) {
 
     List<String> features = new ArrayList<String>();
 
-    for (int i = 0; i < text.length - 1; i++) {
-      features.add("ng=" + text[i] + ":" + text[i + 1]);
+    for (int i = 0; i <= text.length - minGram; i++) {
+      String feature = "ng=";
+      for (int y = 0; y < maxGram && i + y < text.length; y++) {
+        feature = feature + ":" + text[i + y];
+        int gramCount = y + 1;
+        if (maxGram >= gramCount && gramCount >= minGram) {
+          features.add(feature);
+        }
+      }
     }
 
     return features;