diff --git a/primitiveCollections/src/main/java/org/lucares/collections/IntList.java b/primitiveCollections/src/main/java/org/lucares/collections/IntList.java
index feb113d..3cfb94b 100644
--- a/primitiveCollections/src/main/java/org/lucares/collections/IntList.java
+++ b/primitiveCollections/src/main/java/org/lucares/collections/IntList.java
@@ -26,7 +26,6 @@ public final class IntList implements Serializable, Cloneable {
 	// TODO add removeRange
 	// TODO add replace
 	// TODO add lastIndexOf
-	// TODO add indexOf
 	// TODO remove bounds checks that are handled by java, e.g. negative indices
 	// TODO toString
 
@@ -352,6 +351,39 @@ public final class IntList implements Serializable, Cloneable {
 		return StreamSupport.intStream(spliterator, true);
 	}
 
+	/**
+	 * Returns the index of the first occurrence of {@code value}, or -1 if it does
+	 * not exist.
+	 *
+	 * @param value
+	 *            the value
+	 * @return the index, or -1
+	 */
+	public int indexOf(final int value) {
+		return indexOf(value, 0);
+	}
+
+	/**
+	 * Returns the index of the first occurrence of {@code value} starting at the
+	 * {@code offset}'s element, or -1 if it does not exist.
+	 *
+	 * @param value
+	 *            the value
+	 * @param offset
+	 *            the offset
+	 * @return the index, or -1
+	 * @throws ArrayIndexOutOfBoundsException
+	 *             if offset is negative, or larger than the size of the list
+	 */
+	public int indexOf(final int value, final int offset) {
+		for (int i = offset; i < index; i++) {
+			if (data[i] == value) {
+				return i;
+			}
+		}
+		return -1;
+	}
+
 	@Override
 	public String toString() {
 
diff --git a/primitiveCollections/src/test/java/org/lucares/collections/IntListTest.java b/primitiveCollections/src/test/java/org/lucares/collections/IntListTest.java
index 5be1a76..d0294ad 100644
--- a/primitiveCollections/src/test/java/org/lucares/collections/IntListTest.java
+++ b/primitiveCollections/src/test/java/org/lucares/collections/IntListTest.java
@@ -583,4 +583,36 @@ public class IntListTest {
 		Assert.assertNotEquals("should use parallelism during computation", processingOrder.toString(),
 				list.toString());
 	}
+
+	@Test
+	public void testIndexOf() {
+		final IntList list = new IntList();
+		Assert.assertEquals(-1, list.indexOf(0));
+
+		list.add(1);
+		Assert.assertEquals(-1, list.indexOf(0));
+		Assert.assertEquals(0, list.indexOf(1));
+
+		list.add(2);
+		Assert.assertEquals(-1, list.indexOf(0));
+		Assert.assertEquals(0, list.indexOf(1));
+		Assert.assertEquals(1, list.indexOf(2));
+	}
+
+	@Test
+	public void testIndexOfWithOffset() {
+		final IntList list = new IntList();
+		list.addAll(0, 2, 0, 2);
+		Assert.assertEquals(1, list.indexOf(2, 0));
+		Assert.assertEquals(1, list.indexOf(2, 1));
+		Assert.assertEquals(3, list.indexOf(2, 2));
+		Assert.assertEquals(3, list.indexOf(2, 3));
+		Assert.assertEquals(-1, list.indexOf(2, 4));
+
+		// indexed returned by indexOf() are consistent with get()
+		Assert.assertEquals(list.get(list.indexOf(2, 0)), 2);
+		Assert.assertEquals(list.get(list.indexOf(2, 1)), 2);
+		Assert.assertEquals(list.get(list.indexOf(2, 2)), 2);
+		Assert.assertEquals(list.get(list.indexOf(2, 3)), 2);
+	}
 }