diff --git a/Readme.md b/Readme.md
index c8c7556..7a5a969 100644
--- a/Readme.md
+++ b/Readme.md
@@ -41,6 +41,9 @@ levenshtein('saturday', 'sunday'); // 3
 /* Case sensitive! */
 levenshtein('DwAyNE', 'DUANE') !== levenshtein('dwayne', 'DuAnE'); // true
 
+/* Insensitive: */
+levenshtein('DwAyNE', 'DUANE', true) === levenshtein('dwayne', 'DuAnE', true); // true
+
 /* Order insensitive */
 levenshtein('aarrgh', 'aargh') === levenshtein('aargh', 'aarrgh'); // true
 ```
@@ -64,6 +67,7 @@ Options:
 
   -h, --help           output usage information
   -v, --version        output version number
+  -i, --insensitive    ignore casing
 
 Usage:
 
diff --git a/cli.js b/cli.js
index 4bc6c99..36f3997 100755
--- a/cli.js
+++ b/cli.js
@@ -37,6 +37,12 @@ var command;
 
 command = Object.keys(pack.bin)[0];
 
+/*
+ * Whether to ignore case.
+ */
+
+var insensitive = false;
+
 /**
  * Get the distance for words.
  *
@@ -44,7 +50,7 @@ command = Object.keys(pack.bin)[0];
  * @return {number}
  */
 function distance(values) {
-    return levenshtein(values[0], values[1]);
+    return levenshtein(values[0], values[1], insensitive);
 }
 
 /**
@@ -63,6 +69,7 @@ function help() {
         '',
         '  -h, --help           output usage information',
         '  -v, --version        output version number',
+        '  -i, --insensitive    ignore casing',
         '',
         'Usage:',
         '',
@@ -101,17 +108,36 @@ function getDistance(value) {
  * Program.
  */
 
+var index = argv.indexOf('--insensitive');
+
+if (index === -1) {
+    index = argv.indexOf('-i');
+}
+
 if (
     argv.indexOf('--help') !== -1 ||
     argv.indexOf('-h') !== -1
 ) {
     console.log(help());
-} else if (
+
+    return;
+}
+
+if (
     argv.indexOf('--version') !== -1 ||
     argv.indexOf('-v') !== -1
 ) {
     console.log(pack.version);
-} else if (argv.length) {
+
+    return;
+}
+
+if (index !== -1) {
+    argv.splice(index, 1);
+    insensitive = true;
+}
+
+if (argv.length) {
     getDistance(argv.join(' '));
 } else if (!expextPipeIn) {
     getDistance();
diff --git a/index.js b/index.js
index 64f9ec7..68a127b 100644
--- a/index.js
+++ b/index.js
@@ -4,7 +4,7 @@ var cache,
 cache = [];
 codes = [];
 
-function levenshtein(value, other) {
+function levenshtein(value, other, insensitive) {
     var length,
         lengthOther,
         code,
@@ -29,6 +29,11 @@ function levenshtein(value, other) {
         return length;
     }
 
+    if (insensitive) {
+        value = value.toLowerCase();
+        other = other.toLowerCase();
+    }
+
     index = 0;
 
     while (index < length) {
diff --git a/test.js b/test.js
index f50cec8..3276a0a 100644
--- a/test.js
+++ b/test.js
@@ -40,6 +40,13 @@ describe('levenshteinDistance()', function () {
         );
     });
 
+    it('should match case if `insensitive` is given', function () {
+        assert(
+            levenshteinDistance('DwAyNE', 'DUANE', true) ===
+            levenshteinDistance('dwayne', 'DuAnE', true)
+        );
+    });
+
     it('should not care about parameter order', function () {
         assert(
             levenshteinDistance('aarrgh', 'aargh') ===
diff --git a/test.sh b/test.sh
index a6fb6e4..6a64883 100755
--- a/test.sh
+++ b/test.sh
@@ -21,6 +21,18 @@ it "Should accept space seperated values"
     result=`./cli.js "sitting" "kitten"` 2> /dev/null
     assert $result "3"
 
+it "Should be case-sensitive by default"
+    result=`./cli.js "a" "A"` 2> /dev/null
+    assert $result "1"
+
+it "Should be case-insensitive when given \`-i\`"
+    result=`./cli.js -i "a" "A"` 2> /dev/null
+    assert $result "0"
+
+it "Should be case-insensitive when given \`--insensitive\`"
+    result=`./cli.js --insensitive "a" "A"` 2> /dev/null
+    assert $result "0"
+
 it "Should accept comma seperated values"
     result=`./cli.js "sitting,kitten"` 2> /dev/null
     assert $result "3"