diff --git a/.gitignore b/.gitignore
index bee8a64..a51c439 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 __pycache__
+*.sqlite
diff --git a/Pipfile b/Pipfile
index 9d51023..a6a4b07 100644
--- a/Pipfile
+++ b/Pipfile
@@ -13,6 +13,8 @@ pandas = "*"
 python-stdnum = "*"
 xlrd = "*"
 iso-639 = "*"
+requests = "*"
+requests-cache = "*"
 
 [requires]
 python_version = "3.7"
diff --git a/Pipfile.lock b/Pipfile.lock
index 1f79336..edb8cf4 100644
--- a/Pipfile.lock
+++ b/Pipfile.lock
@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "d5c625fc9bd915e3199fc4f617c157ee002795fa44d9fa6f0a298749acc134e6"
+            "sha256": "c5c86b4dae011bcbf6705514d97aa55e0a59dd8b7927c38e34103d77eca13cc7"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -16,6 +16,27 @@
         ]
     },
     "default": {
+        "certifi": {
+            "hashes": [
+                "sha256:046832c04d4e752f37383b628bc601a7ea7211496b4638f6514d0e5b9acc4939",
+                "sha256:945e3ba63a0b9f577b1395204e13c3a231f9bc0223888be653286534e5873695"
+            ],
+            "version": "==2019.6.16"
+        },
+        "chardet": {
+            "hashes": [
+                "sha256:84ab92ed1c4d4f16916e05906b6b75a6c0fb5db821cc65e70cbd64a3e2a5eaae",
+                "sha256:fc323ffcaeaed0e0a02bf4d117757b98aed530d9ed4531e3e15460124c106691"
+            ],
+            "version": "==3.0.4"
+        },
+        "idna": {
+            "hashes": [
+                "sha256:c357b3f628cf53ae2c4c05627ecc484553142ca23264e593d327bcde5e9c3407",
+                "sha256:ea8b7f6188e6fa117537c3df7da9fc686d485087abf6ac197f9c46432f7e4a3c"
+            ],
+            "version": "==2.8"
+        },
         "iso-639": {
             "hashes": [
                 "sha256:dc9cd4b880b898d774c47fe9775167404af8a85dd889d58f9008035109acce49"
@@ -86,6 +107,22 @@
             ],
             "version": "==2019.1"
         },
+        "requests": {
+            "hashes": [
+                "sha256:11e007a8a2aa0323f5a921e9e6a2d7e4e67d9877e85773fba9ba6419025cbeb4",
+                "sha256:9cf5292fcd0f598c671cfc1e0d7d1a7f13bb8085e9a590f48c010551dc6c4b31"
+            ],
+            "index": "pypi",
+            "version": "==2.22.0"
+        },
+        "requests-cache": {
+            "hashes": [
+                "sha256:6822f788c5ee248995c4bfbd725de2002ad710182ba26a666e85b64981866060",
+                "sha256:73a7211870f7d67af5fd81cad2f67cfe1cd3eb4ee6a85155e07613968cc72dfc"
+            ],
+            "index": "pypi",
+            "version": "==0.5.0"
+        },
         "six": {
             "hashes": [
                 "sha256:3350809f0555b11f552448330d0b52d5f24c91a322ea4a15ef22629740f3761c",
@@ -93,6 +130,13 @@
             ],
             "version": "==1.12.0"
         },
+        "urllib3": {
+            "hashes": [
+                "sha256:b246607a25ac80bedac05c6f282e3cdaf3afb65420fd024ac94435cabe6e18d1",
+                "sha256:dbe59173209418ae49d485b87d1681aefa36252ee85884c31346debd19463232"
+            ],
+            "version": "==1.25.3"
+        },
         "xlrd": {
             "hashes": [
                 "sha256:546eb36cee8db40c3eaa46c351e67ffee6eeb5fa2650b71bc4c758a29a1b29b2",
diff --git a/README.md b/README.md
index c57b865..c22bf7e 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,7 @@ Requires Python 3.6 or greater. CSV and Excel support comes from the [Pandas](ht
 - Read Excel files
 - Validate dates, ISSNs, ISBNs, and multi-value separators ("||")
 - Validate languages against ISO 639-2 and ISO 639-3
+- Validate subjects against AGROVOC REST API
 - Fix leading, trailing, and excessive whitespace
 - Fix invalid multi-value separators (`|`) using `--unsafe-fixes`
 - Remove unnecessary Unicode like [non-breaking spaces](https://en.wikipedia.org/wiki/Non-breaking_space), [replacement characters](https://en.wikipedia.org/wiki/Specials_(Unicode_block)#Replacement_character), etc
diff --git a/csv_metadata_quality/app.py b/csv_metadata_quality/app.py
index 49e6640..e30d4cd 100644
--- a/csv_metadata_quality/app.py
+++ b/csv_metadata_quality/app.py
@@ -43,6 +43,11 @@ def main(argv):
         # Fix: duplicate metadata values
         df[column] = df[column].apply(fix.duplicates)
 
+        # Check: invalid AGROVOC subject
+        match = re.match(r'.*?dc\.subject.*$', column)
+        if match is not None:
+            df[column] = df[column].apply(check.agrovoc)
+
         # Check: invalid language
         match = re.match(r'^.*?language.*$', column)
         if match is not None:
diff --git a/csv_metadata_quality/check.py b/csv_metadata_quality/check.py
index 7502a53..f3b0e16 100755
--- a/csv_metadata_quality/check.py
+++ b/csv_metadata_quality/check.py
@@ -189,3 +189,57 @@ def language(field):
             print(f'Invalid language: {value}')
 
     return field
+
+
+def agrovoc(field):
+    """Check subject terms against AGROVOC REST API.
+
+    Logic copied from agrovoc-lookup.py.
+
+    See: https://github.com/ilri/DSpace/blob/5_x-prod/agrovoc-lookup.py
+
+    Prints a warning if the value is invalid.
+    """
+
+    from datetime import timedelta
+    import re
+    import requests
+    import requests_cache
+
+    # Skip fields with missing values
+    if pd.isna(field):
+        return
+
+    # Try to split multi-value field on "||" separator
+    for value in field.split('||'):
+        # match lines beginning with words, paying attention to subjects with
+        # special characters like spaces, quotes, dashes, parentheses, etc:
+        # SUBJECT
+        # ANOTHER SUBJECT
+        # XANTHOMONAS CAMPESTRIS PV. MANIHOTIS
+        # WOMEN'S PARTICIPATION
+        # COMMUNITY-BASED FOREST MANAGEMENT
+        # INTERACCIÓN GENOTIPO AMBIENTE
+        # COCOA (PLANT)
+        pattern = re.compile(r'^[\w\-\.\'\(\)]+?[\w\s\-\.\'\(\)]+$')
+
+        if pattern.match(value):
+            request_url = f'http://agrovoc.uniroma2.it/agrovoc/rest/v1/agrovoc/search?query={value}'
+
+            # enable transparent request cache with thirty days expiry
+            expire_after = timedelta(days=30)
+            requests_cache.install_cache('agrovoc-response-cache', expire_after=expire_after)
+
+            request = requests.get(request_url)
+
+            # prune old cache entries
+            requests_cache.core.remove_expired_responses()
+
+            if request.status_code == requests.codes.ok:
+                data = request.json()
+
+                # check if there is 1 result, ie an exact subject term match
+                if len(data['results']) != 1:
+                    print(f'Invalid AGROVOC subject: {value}')
+
+    return field
diff --git a/tests/test_check.py b/tests/test_check.py
index 527e50b..4880ccd 100644
--- a/tests/test_check.py
+++ b/tests/test_check.py
@@ -169,3 +169,24 @@ def test_check_invalid_language(capsys):
 
     captured = capsys.readouterr()
     assert captured.out == f'Invalid language: {value}\n'
+
+
+def test_check_invalid_agrovoc(capsys):
+    '''Test invalid AGROVOC subject.'''
+
+    value = 'FOREST'
+
+    check.agrovoc(value)
+
+    captured = capsys.readouterr()
+    assert captured.out == f'Invalid AGROVOC subject: {value}\n'
+
+
+def test_check_valid_agrovoc():
+    '''Test valid AGROVOC subject.'''
+
+    value = 'FORESTS'
+
+    result = check.agrovoc(value)
+
+    assert result == value