diff --git a/src/dicognito/idanonymizer.py b/src/dicognito/idanonymizer.py
index d7aa019..24d37e5 100644
--- a/src/dicognito/idanonymizer.py
+++ b/src/dicognito/idanonymizer.py
@@ -54,16 +54,32 @@ class IDAnonymizer:
         True if the element was anonymized, or False if not.
         """
         if data_element.tag in self.id_tags:
-            if isinstance(data_element.value, pydicom.multival.MultiValue):
-                data_element.value = [self._new_id(id) for id in data_element.value]
-            else:
-                data_element.value = self._new_id(data_element.value)
+            self._replace_id(data_element)
             return True
+
+        if self._anonymize_mitra_global_patient_id(dataset, data_element):
+            return True
+
         if data_element.tag == self.issuer_tag and data_element.value:
             data_element.value = "DICOGNITO"
             return True
         return False
 
+    def _anonymize_mitra_global_patient_id(self, dataset, data_element):
+        if data_element.tag.group == 0x0031 and data_element.tag.element % 0x0020 == 0:
+            private_tag_group = data_element.tag.element >> 8
+            if dataset[(0x0031 << 16) + private_tag_group].value == "MITRA LINKED ATTRIBUTES 1.0":
+                self._replace_id(data_element)
+                data_element.value = data_element.value.encode()
+                return True
+        return False
+
+    def _replace_id(self, data_element):
+        if isinstance(data_element.value, pydicom.multival.MultiValue):
+            data_element.value = [self._new_id(id) for id in data_element.value]
+        else:
+            data_element.value = self._new_id(data_element.value)
+
     def _new_id(self, original_value):
         indexes = self.randomizer.get_ints_from_ranges(original_value, *self._indices_for_randomizer)
         id_root = "".join([self._alphabet[i] for i in indexes])
diff --git a/src/dicognito/release_notes.md b/src/dicognito/release_notes.md
index 1ee3fec..5e319e3 100644
--- a/src/dicognito/release_notes.md
+++ b/src/dicognito/release_notes.md
@@ -6,6 +6,7 @@
 ### New
 
 - Anonymize placer- and filler-order numbers ([#58](https://github.com/blairconrad/dicognito/issues/58))
+- Anonymize Mitra Global Patient IDs ([#60](https://github.com/blairconrad/dicognito/issues/60))
 
 ### Fixed
 

Anonymize Mitra Global Patient ID
e.g.

```
0031 0011       28 | private_creator                      | LO |   1 | "MITRA LINKED ATTRIBUTES 1.0"
0031 1120       10 | Unknown element                      | Unkn |  ?  | "GPIAPCB136"
```
diff --git a/tests/test_anonymize_private_tags.py b/tests/test_anonymize_private_tags.py
new file mode 100644
index 0000000..af8ec28
--- /dev/null
+++ b/tests/test_anonymize_private_tags.py
@@ -0,0 +1,18 @@
+from dicognito.anonymizer import Anonymizer
+
+from .data_for_tests import load_test_instance
+
+
+def test_mitra_global_patient_id_is_updated():
+    with load_test_instance() as dataset:
+
+        block = dataset.private_block(0x0031, "MITRA LINKED ATTRIBUTES 1.0", create=True)
+        block.add_new(0x20, "LO", "GPIYMBB54")
+
+        anonymizer = Anonymizer()
+        anonymizer.anonymize(dataset)
+
+        block = dataset.private_block(0x0031, "MITRA LINKED ATTRIBUTES 1.0")
+        actual = block[0x20].value
+
+        assert actual != "GPIYMBB54"

pip install -e .[dev]
parse_log_pytest
pytest
pydicom>=1.3 pytest pytest-black flake8 pep8-naming
apt-get update apt-get install -y gcc
3.7
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
attrs @ file:///croot/attrs_1668696182826/work
black==23.3.0
certifi @ file:///croot/certifi_1671487769961/work/certifi
click==8.1.8
-e git+https://github.com/blairconrad/dicognito.git@a5c3fc767564aa643c7a6b5ca1098168b0d9e977#egg=dicognito
flake8==5.0.4
flit_core @ file:///opt/conda/conda-bld/flit-core_1644941570762/work/source/flit_core
importlib-metadata==4.2.0
iniconfig @ file:///home/linux1/recipes/ci/iniconfig_1610983019677/work
mccabe==0.7.0
mypy-extensions==1.0.0
packaging @ file:///croot/packaging_1671697413597/work
pathspec==0.11.2
pep8-naming==0.14.0
platformdirs==4.0.0
pluggy @ file:///tmp/build/80754af9/pluggy_1648042572264/work
py @ file:///opt/conda/conda-bld/py_1644396412707/work
pycodestyle==2.9.1
pydicom==2.4.4
pyflakes==2.5.0
pytest==7.1.2
pytest-black==0.6.0
toml==0.10.2
tomli @ file:///opt/conda/conda-bld/tomli_1657175507142/work
typed-ast==1.5.5
typing_extensions==4.7.1
zipp @ file:///croot/zipp_1672387121353/work

name: dicognito
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - attrs=22.1.0=py37h06a4308_0
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2022.12.7=py37h06a4308_0
  - flit-core=3.6.0=pyhd3eb1b0_0
  - importlib_metadata=4.11.3=hd3eb1b0_0
  - iniconfig=1.1.1=pyhd3eb1b0_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - packaging=22.0=py37h06a4308_0
  - pip=22.3.1=py37h06a4308_0
  - pluggy=1.0.0=py37h06a4308_1
  - py=1.11.0=pyhd3eb1b0_0
  - pytest=7.1.2=py37h06a4308_0
  - python=3.7.16=h7a1cb2a_0
  - readline=8.2=h5eee18b_0
  - setuptools=65.6.3=py37h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - tomli=2.0.1=py37h06a4308_0
  - wheel=0.38.4=py37h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zipp=3.11.0=py37h06a4308_0
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - black==23.3.0
      - click==8.1.8
      - dicognito==0.7.1
      - flake8==5.0.4
      - importlib-metadata==4.2.0
      - mccabe==0.7.0
      - mypy-extensions==1.0.0
      - pathspec==0.11.2
      - pep8-naming==0.14.0
      - platformdirs==4.0.0
      - pycodestyle==2.9.1
      - pydicom==2.4.4
      - pyflakes==2.5.0
      - pytest-black==0.6.0
      - toml==0.10.2
      - typed-ast==1.5.5
      - typing-extensions==4.7.1
prefix: /opt/conda/envs/dicognito

tests/test_anonymize_private_tags.py::test_mitra_global_patient_id_is_updated
src/dicognito/idanonymizer.py src/dicognito/release_notes.md
src/dicognito/idanonymizer.py src/dicognito/release_notes.md