diff --git a/stella-core/src/main/java/br/com/caelum/stella/DigitoPara.java b/stella-core/src/main/java/br/com/caelum/stella/DigitoPara.java
index e66914c6..9f3c8314 100644
--- a/stella-core/src/main/java/br/com/caelum/stella/DigitoPara.java
+++ b/stella-core/src/main/java/br/com/caelum/stella/DigitoPara.java
@@ -35,6 +35,7 @@
  */
 public class DigitoPara {
 
+	private static final int ZERO_ASCII = 48;
 	private LinkedList<Integer> numero;
 	private List<Integer> multiplicadores = new ArrayList<Integer>();
 	private boolean complementar;
@@ -56,7 +57,7 @@ public DigitoPara(String trecho) {
 		this.numero = new LinkedList<Integer>();
 		char[] digitos = trecho.toCharArray();
 		for (char digito : digitos) {
-			this.numero.add(Character.getNumericValue(digito));
+			this.numero.add(((int) digito) - ZERO_ASCII);
 		}
 		Collections.reverse(numero);
 	}
diff --git a/stella-core/src/main/java/br/com/caelum/stella/validation/CNPJValidator.java b/stella-core/src/main/java/br/com/caelum/stella/validation/CNPJValidator.java
index fc6429b3..0fa3728b 100644
--- a/stella-core/src/main/java/br/com/caelum/stella/validation/CNPJValidator.java
+++ b/stella-core/src/main/java/br/com/caelum/stella/validation/CNPJValidator.java
@@ -19,8 +19,10 @@
  */
 public class CNPJValidator implements Validator<String> {
 
-    public static final Pattern FORMATED = Pattern.compile("(\\d{2})[.](\\d{3})[.](\\d{3})/(\\d{4})-(\\d{2})");
-    public static final Pattern UNFORMATED = Pattern.compile("(\\d{2})(\\d{3})(\\d{3})(\\d{4})(\\d{2})");
+    public static final Pattern FORMATED = Pattern.compile(
+            "([0-9A-Z]{2})[.]([0-9A-Z]{3})[.]([0-9A-Z]{3})/([0-9A-Z]{4})-([0-9A-Z]{2})");
+    public static final Pattern UNFORMATED = Pattern.compile(
+            "([0-9A-Z]{2})([0-9A-Z]{3})([0-9A-Z]{3})([0-9A-Z]{4})([0-9A-Z]{2})");
 	
     private boolean isFormatted = false;
     private boolean isIgnoringRepeatedDigits;
@@ -97,8 +99,8 @@ private List<ValidationMessage> getInvalidValues(String cnpj) {
         		errors.add(messageProducer.getMessage(CNPJError.INVALID_DIGITS));
         		return errors;
         	}
-        	
-            if(unformatedCNPJ.length() != 14 || !unformatedCNPJ.matches("[0-9]*")){
+
+            if (unformatedCNPJ.length() != 14 || !unformatedCNPJ.matches("[0-9A-Z]*")) {
             	errors.add(messageProducer.getMessage(CNPJError.INVALID_DIGITS));
             }
             
diff --git a/stella-core/src/test/java/br/com/caelum/stella/validation/CNPJValidatorTest.java b/stella-core/src/test/java/br/com/caelum/stella/validation/CNPJValidatorTest.java
index c2b28dd6..7070b0d2 100644
--- a/stella-core/src/test/java/br/com/caelum/stella/validation/CNPJValidatorTest.java
+++ b/stella-core/src/test/java/br/com/caelum/stella/validation/CNPJValidatorTest.java
@@ -21,7 +21,11 @@ public class CNPJValidatorTest {
 	private final String validString = "26.637.142/0001-58";
 	private final String validStringNotFormatted = "26637142000158";
 
+    private final String validStringAlpha = "12.ABC.345/01DE-35";
+    private final String validStringAlphaNotFormatted = "12ABC34501DE35";
+
     private final String firstCheckDigitWrongNotFormatted = "26637142000168";
+    private final String alphaFirstCheckDigitWrongNotFormatted = "12ABC34501DE45";
 
     @Test
     public void shouldHaveDefaultConstructorThatUsesSimpleMessageProducerAndAssumesThatStringIsNotFormatted() {
@@ -34,6 +38,14 @@ public void shouldHaveDefaultConstructorThatUsesSimpleMessageProducerAndAssumesT
             InvalidStateException invalidStateException = (InvalidStateException) e;
             assertMessage(invalidStateException, INVALID_CHECK_DIGITS);
         }
+
+        try {
+            new CNPJValidator().assertValid(alphaFirstCheckDigitWrongNotFormatted);
+            fail("Test expected to throw exception");
+        } catch (InvalidStateException e) {
+            InvalidStateException invalidStateException = (InvalidStateException) e;
+            assertMessage(invalidStateException, INVALID_CHECK_DIGITS);
+        }
     }
 
 	private void assertMessage(InvalidStateException invalidStateException, String expected) {
@@ -87,6 +99,7 @@ public void shouldValidateValidCNPJ() {
         validator.assertValid("63025530002409");
         validator.assertValid("61519128000150");
         validator.assertValid("68745386000102");
+        validator.assertValid("12ABC34501DE35");
     }
 
     @Test
@@ -186,6 +199,9 @@ public void shouldBeEligibleDefaultConstructor() {
         final CNPJValidator cnpjValidator = new CNPJValidator();
         assertTrue(cnpjValidator.isEligible(validStringNotFormatted));
         assertFalse(cnpjValidator.isEligible(validString));
+
+        assertTrue(cnpjValidator.isEligible(validStringAlphaNotFormatted));
+        assertFalse(cnpjValidator.isEligible(validStringAlpha));
     }
 
     @Test
@@ -193,6 +209,9 @@ public void shouldBeEligibleConstructorNotFormatted() {
         final CNPJValidator cnpjValidator = new CNPJValidator(false);
         assertTrue(cnpjValidator.isEligible(validStringNotFormatted));
         assertFalse(cnpjValidator.isEligible(validString));
+
+        assertTrue(cnpjValidator.isEligible(validStringAlphaNotFormatted));
+        assertFalse(cnpjValidator.isEligible(validStringAlpha));
     }
 
     @Test
@@ -200,6 +219,9 @@ public void shouldBeEligibleConstructorFormatted() {
         final CNPJValidator cnpjValidator = new CNPJValidator(true);
         assertFalse(cnpjValidator.isEligible(validStringNotFormatted));
         assertTrue(cnpjValidator.isEligible(validString));
+
+        assertFalse(cnpjValidator.isEligible(validStringAlphaNotFormatted));
+        assertTrue(cnpjValidator.isEligible(validStringAlpha));
     }
 
     @Test