diff --git a/CHANGELOG.md b/CHANGELOG.md
index a8d204d..1074ade 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Utilitário `list_all_legal_nature` [#653](https://github.com/brazilian-utils/python/pull/653)
 - Utilitário `is_valid_cnh` [#651](https://github.com/brazilian-utils/brutils-python/pull/651)
 - Utilitário `is_valid_renavam` [#652](https://github.com/brazilian-utils/brutils-python/pull/652)
+- Suporte a CNPJ alfanumérico em `is_valid_cnpj`, `format_cnpj` e `remove_symbols_cnpj`
 
 ### Fixed
 
diff --git a/README.md b/README.md
index a24fffa..bcf204b 100644
--- a/README.md
+++ b/README.md
@@ -228,6 +228,8 @@ Exemplo:
 True
 >>> is_valid_cnpj('00111222000133')
 False
+>>> is_valid_cnpj('12ABC34501DE35')
+True
 ```
 
 ### format_cnpj
@@ -276,6 +278,8 @@ Exemplo:
 >>> from brutils import remove_symbols_cnpj
 >>> remove_symbols_cnpj('00.111.222/0001-00')
 '00111222000100'
+>>> remove_symbols_cnpj('12.ABC.345/01DE-35')
+'12ABC34501DE35'
 ```
 
 ### generate_cnpj
diff --git a/README_EN.md b/README_EN.md
index aa784da..4d1a6f7 100644
--- a/README_EN.md
+++ b/README_EN.md
@@ -229,6 +229,8 @@ Example:
 True
 >>> is_valid_cnpj('00111222000133')
 False
+>>> is_valid_cnpj('12ABC34501DE35')
+True
 ```
 
 ### format_cnpj
@@ -278,6 +280,8 @@ Example:
 >>> from brutils import remove_symbols_cnpj
 >>> remove_symbols_cnpj('00.111.222/0001-00')
 '00111222000100'
+>>> remove_symbols_cnpj('12.ABC.345/01DE-35')
+'12ABC34501DE35'
 ```
 
 ### generate_cnpj
diff --git a/brutils/cnpj.py b/brutils/cnpj.py
index 84dd7ae..228a9ef 100644
--- a/brutils/cnpj.py
+++ b/brutils/cnpj.py
@@ -151,7 +151,7 @@ def validate(cnpj: str) -> bool:
        backward compatibility.
     """
 
-    if not cnpj.isdigit() or len(cnpj) != 14 or len(set(cnpj)) == 1:
+    if len(cnpj) != 14 or len(set(cnpj)) == 1:
         return False
     return all(
         _hashdigit(cnpj, i + 13) == int(v) for i, v in enumerate(cnpj[12:])
@@ -230,7 +230,8 @@ def _hashdigit(cnpj: str, position: int) -> int:
 
     weightgen = chain(range(position - 8, 1, -1), range(9, 1, -1))
     val = (
-        sum(int(digit) * weight for digit, weight in zip(cnpj, weightgen)) % 11
+        sum((ord(char) - 48) * weight for char, weight in zip(cnpj, weightgen))
+        % 11
     )
     return 0 if val < 2 else 11 - val
 
diff --git a/tests/test_cnpj.py b/tests/test_cnpj.py
index 2ec7261..927aa8e 100644
--- a/tests/test_cnpj.py
+++ b/tests/test_cnpj.py
@@ -35,6 +35,10 @@ def test_validate(self):
         self.assertIs(validate("34665388000161"), True)
         self.assertIs(validate("52599927000100"), False)
         self.assertIs(validate("00000000000"), False)
+        self.assertIs(validate("12ABC34501DE35"), True)
+        self.assertIs(validate("12ABC34501DE00"), False)
+        self.assertIs(validate("AAAAAAAAAAAAAA"), False)
+        self.assertIs(validate("12ABC34501DE3"), False)
 
     def test_is_valid(self):
         # When CNPJ is not string, returns False
@@ -66,6 +70,7 @@ def test_is_valid(self):
         # When CNPJ is valid
         self.assertIs(is_valid("34665388000161"), True)
         self.assertIs(is_valid("01838723000127"), True)
+        self.assertIs(is_valid("12ABC34501DE35"), True)
 
     def test_generate(self):
         for _ in range(10_000):
@@ -77,10 +82,15 @@ def test__hashdigit(self):
         self.assertEqual(_hashdigit("00000000000000", 14), 0)
         self.assertEqual(_hashdigit("52513127000292", 13), 9)
         self.assertEqual(_hashdigit("52513127000292", 14), 9)
+        self.assertEqual(_hashdigit("12ABC34501DE", 13), 3)
+        self.assertEqual(_hashdigit("12ABC34501DE3", 14), 5)
 
     def test__checksum(self):
         self.assertEqual(_checksum("00000000000000"), "00")
         self.assertEqual(_checksum("52513127000299"), "99")
+        self.assertEqual(_checksum("12ABC34501DE35"), "35")
+        self.assertEqual(_checksum("1345C3A50001"), "06")
+        self.assertEqual(_checksum("R55231B30007"), "57")
 
 
 @patch("brutils.cnpj.sieve")
@@ -89,6 +99,8 @@ def test_remove_symbols(self, mock_sieve):
         # When call remove_symbols, it calls sieve
         remove_symbols("12.345.678/0001-90")
         mock_sieve.assert_called()
+        remove_symbols("12.ABC.345/01DE-35")
+        mock_sieve.assert_called()
 
 
 @patch("brutils.cnpj.is_valid")
@@ -102,6 +114,13 @@ def test_when_cnpj_is_valid_returns_true_to_format(self, mock_is_valid):
         # Checks if function is_valid_cnpj is called
         mock_is_valid.assert_called_once_with("01838723000127")
 
+        mock_is_valid.reset_mock()
+        # When cnpj is_valid, returns formatted cnpj
+        self.assertEqual(format_cnpj("12ABC34501DE35"), "12.ABC.345/01DE-35")
+
+        # Checks if function is_valid_cnpj is called
+        mock_is_valid.assert_called_once_with("12ABC34501DE35")
+
     def test_when_cnpj_is_not_valid_returns_none(self, mock_is_valid):
         mock_is_valid.return_value = False