diff --git a/README.md b/README.md
index 39883c5c2..f501b42ac 100644
--- a/README.md
+++ b/README.md
@@ -204,7 +204,6 @@ This will show the list of validation options.
                                   if both .env and -me <limit> are specified, the larger value will be used.  If either sets the per_dataset_flag to true, it will be true
                                   If limit is set to 0, no maximum will be enforced.
                                   No maximum is the default behavior.
-  -dv, --define-version TEXT      Define-XML version used for validation
   -dxp, --define-xml-path         Path to define-xml file.
   -vx, --validate-xml             Enable XML validation (default 'y' to enable, otherwise disable).
   --whodrug TEXT                  Path to directory with WHODrug dictionary
diff --git a/cdisc_rules_engine/models/validation_args.py b/cdisc_rules_engine/models/validation_args.py
index bf1d60083..713560eed 100644
--- a/cdisc_rules_engine/models/validation_args.py
+++ b/cdisc_rules_engine/models/validation_args.py
@@ -16,7 +16,6 @@
         "output",
         "output_format",
         "raw_report",
-        "define_version",
         "external_dictionaries",
         "rules",
         "exclude_rules",
diff --git a/cdisc_rules_engine/services/reporting/sdtm_report_data.py b/cdisc_rules_engine/services/reporting/sdtm_report_data.py
index b197c8cf8..5ab0d8e7a 100644
--- a/cdisc_rules_engine/services/reporting/sdtm_report_data.py
+++ b/cdisc_rules_engine/services/reporting/sdtm_report_data.py
@@ -50,10 +50,9 @@ def __init__(
         )
         define_xml_path = args.define_xml_path
         dictionary_versions = self._dictionary_versions or {}
-        if define_xml_path:
-            define_version = self.get_define_version([define_xml_path])
-        else:
-            define_version: str = self._args.define_version
+        define_version = (
+            self.get_define_version([define_xml_path]) if define_xml_path else None
+        )
         controlled_terminology = self._args.controlled_terminology_package
         if not controlled_terminology and define_version:
             if define_xml_path and define_version:
diff --git a/core.py b/core.py
index ffd451e7e..9d13312bc 100644
--- a/core.py
+++ b/core.py
@@ -315,12 +315,6 @@ def _validate_no_arguments(logger) -> None:
         "This flag must be used only with --output-format JSON."
     ),
 )
-@click.option(
-    "-dv",
-    "--define-version",
-    type=click.Choice(["2-1", "2-0", "2.0", "2.1"]),
-    help="Define-XML version used for validation",
-)
 @click.option("--whodrug", help="Path to directory with WHODrug dictionary files")
 @click.option("--meddra", help="Path to directory with MedDRA dictionary files")
 @click.option("--loinc", help="Path to directory with LOINC dictionary files")
@@ -443,7 +437,6 @@ def validate(  # noqa
     output: str,
     output_format: tuple[str],
     raw_report: bool,
-    define_version: str,
     whodrug: str,
     meddra: str,
     loinc: str,
@@ -558,7 +551,6 @@ def validate(  # noqa
             output,
             set(output_format),
             raw_report,
-            define_version,
             external_dictionaries,
             rules,
             exclude_rules,
@@ -930,7 +922,6 @@ def test_validate(filetype):
                     output,
                     output_format,
                     False,
-                    None,
                     external_dictionaries,
                     [],
                     [],
diff --git a/tests/QARegressionTests/test_Issues/test_CoreIssue1345.py b/tests/QARegressionTests/test_Issues/test_CoreIssue1345.py
index 5ac320c88..2b66a4e3a 100644
--- a/tests/QARegressionTests/test_Issues/test_CoreIssue1345.py
+++ b/tests/QARegressionTests/test_Issues/test_CoreIssue1345.py
@@ -18,8 +18,6 @@ def generate_report():
         "sdtmig",
         "-v",
         "3-4",
-        "-dv",
-        "2-1",
         "-dxp",
         os.path.join(
             "tests",
diff --git a/tests/QARegressionTests/test_core/test_validate.py b/tests/QARegressionTests/test_core/test_validate.py
index 14748fd3e..54fa64310 100644
--- a/tests/QARegressionTests/test_core/test_validate.py
+++ b/tests/QARegressionTests/test_core/test_validate.py
@@ -156,7 +156,7 @@ def test_validate_all_options(self):
             "-of",
             "json",
             "-rr",
-            "-dv",
+            "-dxp",
             os.path.join("tests", "resources", "report_test_data", "define.xml"),
             "--whodrug",
             os.path.join("tests", "resources", "dictionaries", "whodrug"),
@@ -513,7 +513,6 @@ def test_validate_dummy_with_all_options_one_data_source(self):
             f"--meddra {os.path.join('tests', 'resources', 'dictionaries', 'meddra')} "
             f"-s sdtmig "
             f"-v 3.4 "
-            f"-dv 2.1 "
             f"-dxp {os.path.join('tests', 'resources', 'define.xml')} "
             f"-l error"
         )
@@ -534,7 +533,6 @@ def test_validate_dummy_with_all_options(self):
             f"--meddra {os.path.join('tests', 'resources', 'dictionaries', 'meddra')} "
             f"-s sdtmig "
             f"-v 3.4 "
-            f"-dv 2.1 "
             f"-dxp {os.path.join('tests', 'resources', 'define.xml')} "
             f"-l error"
         )
@@ -621,7 +619,6 @@ def test_validate_dummy_with_vx_as_no(self):
             f"python core.py validate "
             f"-s sendig "
             f"-v 3.1 "
-            f"-dv 2.1 "
             f"-lr {os.path.join('tests', 'resources', 'CoreIssue295', 'SEND4.json')} "
             f"-dp {os.path.join('tests', 'resources', 'CoreIssue295', 'dm.json')} "
             f"-vx no"
@@ -634,7 +631,6 @@ def test_validate_dummy_with_vx_as_yes(self):
             f"python core.py validate "
             f"-s sendig "
             f"-v 3.1 "
-            f"-dv 2.1 "
             f"-lr {os.path.join('tests', 'resources', 'CoreIssue295', 'SEND4.json')} "
             f"-dp {os.path.join('tests', 'resources', 'CoreIssue295', 'dm.json')} "
             f"-vx y"
diff --git a/tests/unit/test_services/test_data_service/test_data_service.py b/tests/unit/test_services/test_data_service/test_data_service.py
index c3316d4d2..37584bfbb 100644
--- a/tests/unit/test_services/test_data_service/test_data_service.py
+++ b/tests/unit/test_services/test_data_service/test_data_service.py
@@ -195,7 +195,6 @@ def test_get_dataset_class(dataset_metadata, data, expected_class):
             "",
             "",
             False,
-            "",
             None,
             None,
             "",
@@ -281,7 +280,6 @@ def test_get_dataset_class_associated_domains():
                 "",
                 "",
                 False,
-                "",
                 None,
                 None,
                 "",