diff --git a/stdnum/my/__init__.py b/stdnum/my/__init__.py
index e20908ed..949f3950 100644
--- a/stdnum/my/__init__.py
+++ b/stdnum/my/__init__.py
@@ -2,6 +2,7 @@
 # coding: utf-8
 #
 # Copyright (C) 2013 Arthur de Jong
+# Copyright (C) 2023 Leandro Regueiro
 #
 # This library is free software; you can redistribute it and/or
 # modify it under the terms of the GNU Lesser General Public
@@ -19,3 +20,6 @@
 # 02110-1301 USA
 
 """Collection of Malaysian numbers."""
+
+# provide aliases
+from stdnum.my import itn as vat  # noqa: F401
diff --git a/stdnum/my/itn.py b/stdnum/my/itn.py
new file mode 100644
index 00000000..f84284e5
--- /dev/null
+++ b/stdnum/my/itn.py
@@ -0,0 +1,142 @@
+# itn.py - functions for handling ITN numbers
+#
+# Copyright (C) 2020 Sergi Almacellas Abellana
+# Copyright (C) 2023 Leandro Regueiro
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301 USA
+
+"""ITN No. (Malaysian Income Tax Number)
+
+The number is assigned by The Inland Revenue Board of Malaysia (IRBM) and it
+is required to report the income. This unique number is known as
+"Nombor Cukai Pendapatan" or Income Tax Number (ITN).
+
+For individuals the ITN consists on the 2 letters Type of File Number (SG for
+individual resident or OG for individual non-resident) followed by a space, and
+ending with the Income Tax Number (maximum 11 digits).
+
+For Non-Individuals the ITN consists on the Type of File Number (1 or 2 letters)
+followed by a space, and ending with the Income Tax Number (maximum 10 digits).
+The Type of File Number for Non-Individuals can be one of the following:
+
+* C: Company, Pte. Ltd. Company, Limited Company or Non-Resident Company.
+* CS: Cooperative Society.
+* D: Partnership.
+* E: Employer.
+* F: Association.
+* FA: Non-Resident Public Entertainer.
+* PT: Limited Liability Partnership.
+* TA: Trust Body.
+* TC: Unit Trust/ Property Trust.
+* TN: Business Trust.
+* TR: Real Estate Investment Trust/ Property Trust Fund.
+* TP: Deceased Person's Estate.
+* TJ: Hindu Joint Family.
+* LE: Labuan Entity.
+
+>>> validate('SG 10234567090')
+'SG10234567090'
+>>> validate('OG 25845632021')
+'OG25845632021'
+>>> validate('C 2584563202')
+'C2584563202'
+>>> validate('1')
+Traceback (most recent call last):
+    ...
+InvalidComponent: ...
+>>> validate('12345678901234')
+Traceback (most recent call last):
+    ...
+InvalidComponent: ...
+>>> validate('12345')
+Traceback (most recent call last):
+    ...
+InvalidComponent: ...
+>>> validate('X 12345')
+Traceback (most recent call last):
+    ...
+InvalidComponent: ...
+>>> validate('C 12345X')
+Traceback (most recent call last):
+    ...
+InvalidFormat: ...
+>>> format('C2584563202')
+'C 2584563202'
+>>> format('SG10234567090')
+'SG 10234567090'
+"""
+
+from stdnum.exceptions import *
+from stdnum.util import clean, isdigits
+
+
+PREFIXES_11_DIGITS = ('SG', 'OG')
+PREFIXES_10_DIGITS = ('C', 'CS', 'D', 'E', 'F', 'FA', 'PT', 'TA', 'TC', 'TN',
+                      'TR', 'TP', 'TJ', 'LE')
+VALID_PREFIXES = PREFIXES_11_DIGITS + PREFIXES_10_DIGITS
+
+
+def _get_prefix_and_number(number):
+    """Return the number separated in prefix and numerical part.
+
+    This assumes the number has been previously compacted.
+    """
+    for i, c in enumerate(number):
+        if c.isdigit():
+            return number[:i], number[i:]
+    return number, ''
+
+
+def compact(number):
+    """Convert the number to the minimal representation.
+
+    This strips the number of any valid separators and removes surrounding
+    whitespace.
+    """
+    return clean(number, ' -*').strip().upper()
+
+
+def validate(number):
+    """Check if the number is a valid ITN number.
+
+    This checks the length and formatting.
+    """
+    number = compact(number)
+    prefix, digits = _get_prefix_and_number(number)
+    if prefix not in VALID_PREFIXES:
+        raise InvalidComponent()
+    if not digits:
+        raise InvalidComponent()
+    if prefix in PREFIXES_11_DIGITS and len(digits) > 11:
+        raise InvalidComponent()
+    if prefix in PREFIXES_10_DIGITS and len(digits) > 10:
+        raise InvalidComponent()
+    if not isdigits(digits):
+        raise InvalidFormat()
+    return number
+
+
+def is_valid(number):
+    """Check if the number is a valid ITN number."""
+    try:
+        return bool(validate(number))
+    except ValidationError:
+        return False
+
+
+def format(number):
+    """Reformat the number to the standard presentation format."""
+    return ' '.join(_get_prefix_and_number(compact(number)))
diff --git a/tests/test_my_itn.doctest b/tests/test_my_itn.doctest
new file mode 100644
index 00000000..0dae3a3e
--- /dev/null
+++ b/tests/test_my_itn.doctest
@@ -0,0 +1,82 @@
+test_my_itn.doctest - more detailed doctests for stdnum.my.itn module
+
+Copyright (C) 2023 Leandro Regueiro
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA
+
+
+This file contains more detailed doctests for the stdnum.my.itn module. It
+tries to test more corner cases and detailed functionality that is not really
+useful as module documentation.
+
+>>> from stdnum.my import itn
+
+
+Tests for some corner cases.
+
+>>> itn.validate('SG 10234567090')
+'SG10234567090'
+>>> itn.validate('OG 25845632021')
+'OG25845632021'
+>>> itn.validate('C 2584563202')
+'C2584563202'
+>>> itn.validate('X 12345')
+Traceback (most recent call last):
+    ...
+InvalidComponent: ...
+>>> itn.validate('12345')
+Traceback (most recent call last):
+    ...
+InvalidComponent: ...
+>>> itn.validate('C')
+Traceback (most recent call last):
+    ...
+InvalidComponent: ...
+>>> itn.validate('SG 123456789012')
+Traceback (most recent call last):
+    ...
+InvalidComponent: ...
+>>> itn.validate('C 12345678901')
+Traceback (most recent call last):
+    ...
+InvalidComponent: ...
+>>> itn.validate('C 12345X')
+Traceback (most recent call last):
+    ...
+InvalidFormat: ...
+>>> itn.format('C2584563202')
+'C 2584563202'
+>>> itn.format('SG10234567090')
+'SG 10234567090'
+
+
+These have been found online and should all be valid numbers.
+
+>>> numbers = '''
+...
+... C 2128186207
+... C 2354867110
+... C 2493192407
+... F 1064671704
+... OG 04455987090
+... SG 2178656-09
+... SG 10234567090
+... OG 25845632021
+... C 2584563202
+...
+... '''
+>>> [x for x in numbers.splitlines() if x and not itn.is_valid(x)]
+[]