diff --git a/lib/revalidator.js b/lib/revalidator.js
index 0c0160f..5ee3e42 100644
--- a/lib/revalidator.js
+++ b/lib/revalidator.js
@@ -321,7 +321,7 @@
 
       switch (type || (isArray(value) ? 'array' : typeof value)) {
         case 'string':
-          constrain('allowEmpty', value,        function (a, e) { return e ? e : a !== '' });
+          constrain('allowEmpty', value,        function (a, e) { return e ? e : a.trim() !== '' });
           constrain('minLength',  value.length, function (a, e) { return a >= e });
           constrain('maxLength',  value.length, function (a, e) { return a <= e });
           constrain('pattern',    value,        function (a, e) {
diff --git a/test/validator-test.js b/test/validator-test.js
index 195b690..55eaa44 100644
--- a/test/validator-test.js
+++ b/test/validator-test.js
@@ -112,6 +112,7 @@ vows.describe('revalidator', {
     "with <maxLength>":           assertValidates ("boom",   "kaboom",   { maxLength: 4 }),
     "with <minLength>":           assertValidates ("kaboom", "boom",     { minLength: 6 }),
     "with <allowEmpty>":          assertValidates ("hello",  "",         { allowEmpty: false }),
+    "with <allowEmpty>":          assertValidates ("a b",  "  ",         { allowEmpty: false }),
     "with <minimum>":             assertValidates ( 512,      43,        { minimum:   473 }),
     "with <maximum>":             assertValidates ( 512,      1949,      { maximum:   678 }),
     "with <divisibleBy>":         assertValidates ( 10,       9,         { divisibleBy: 5 }),