diff --git a/strictdoc/backend/excel/import_/excel_to_sdoc_converter.py b/strictdoc/backend/excel/import_/excel_to_sdoc_converter.py
index ca8c3096c..a83cc544e 100644
--- a/strictdoc/backend/excel/import_/excel_to_sdoc_converter.py
+++ b/strictdoc/backend/excel/import_/excel_to_sdoc_converter.py
@@ -177,7 +177,9 @@ def create_requirement(
             comments=comments,
         )
         if parent_uid is not None:
-            reference = ParentReqReference(template_requirement, parent_uid)
+            reference = ParentReqReference(
+                template_requirement, parent_uid, relation_uid=None
+            )
 
             requirement_field = RequirementField(
                 parent=template_requirement,
diff --git a/strictdoc/backend/reqif/p01_sdoc/reqif_to_sdoc_converter.py b/strictdoc/backend/reqif/p01_sdoc/reqif_to_sdoc_converter.py
index da087742e..b92b769fa 100644
--- a/strictdoc/backend/reqif/p01_sdoc/reqif_to_sdoc_converter.py
+++ b/strictdoc/backend/reqif/p01_sdoc/reqif_to_sdoc_converter.py
@@ -432,6 +432,7 @@ def create_requirement_from_spec_object(
                         parent_spec_object_parent.attribute_map[
                             foreign_key_id_or_none
                         ].value,
+                        relation_uid=None,
                     )
                 )
             if len(parent_refs) > 0:
diff --git a/strictdoc/backend/reqif/p11_polarion/reqif_to_sdoc_converter.py b/strictdoc/backend/reqif/p11_polarion/reqif_to_sdoc_converter.py
index 21f6ccdaa..ed555767d 100644
--- a/strictdoc/backend/reqif/p11_polarion/reqif_to_sdoc_converter.py
+++ b/strictdoc/backend/reqif/p11_polarion/reqif_to_sdoc_converter.py
@@ -442,6 +442,7 @@ def _p11_create_requirement_from_spec_object(
                         parent_spec_object_parent.attribute_map[
                             foreign_key_id_or_none
                         ].value,
+                        relation_uid=None,
                     )
                 )
             if len(parent_refs) > 0:
diff --git a/strictdoc/backend/sdoc/grammar/type_system.py b/strictdoc/backend/sdoc/grammar/type_system.py
index 4071337ff..2f3ac60ea 100644
--- a/strictdoc/backend/sdoc/grammar/type_system.py
+++ b/strictdoc/backend/sdoc/grammar/type_system.py
@@ -28,6 +28,7 @@
 ParentReqReference[noskipws]:
   '- TYPE: Parent' '\n'
   '  VALUE: ' ref_uid = /.*$/ '\n'
+  ('  RELATION: ' relation_uid = /.+$/ '\n')?
 ;
 
 ChildReqReference[noskipws]:
diff --git a/strictdoc/backend/sdoc/models/reference.py b/strictdoc/backend/sdoc/models/reference.py
index 6f5155163..81f0dc241 100644
--- a/strictdoc/backend/sdoc/models/reference.py
+++ b/strictdoc/backend/sdoc/models/reference.py
@@ -30,9 +30,17 @@ def get_file_format(self) -> Optional[str]:
 
 @auto_described
 class ParentReqReference(Reference):
-    def __init__(self, parent, ref_uid):
+    def __init__(self, parent, ref_uid: str, relation_uid: Optional[str]):
         super().__init__(ReferenceType.PARENT, parent)
-        self.ref_uid = ref_uid
+        self.ref_uid: str = ref_uid
+        # When RELATION: field is not provided for a parent reference, the
+        # textX still passes relation_uid as an empty string (instead of None
+        # as one could expect).
+        self.relation_uid: Optional[str] = (
+            relation_uid
+            if relation_uid is not None and len(relation_uid) > 0
+            else None
+        )
 
 
 @auto_described
diff --git a/strictdoc/backend/sdoc/writer.py b/strictdoc/backend/sdoc/writer.py
index f9bb79d73..9b8512237 100644
--- a/strictdoc/backend/sdoc/writer.py
+++ b/strictdoc/backend/sdoc/writer.py
@@ -238,6 +238,10 @@ def _print_requirement_fields(
                             output += "  VALUE: "
                             output += ref.ref_uid
                             output += "\n"
+                            if reference.relation_uid is not None:
+                                output += "  RELATION: "
+                                output += ref.relation_uid
+                                output += "\n"
 
                 elif field.field_value is not None:
                     if len(field.field_value) > 0:
diff --git a/strictdoc/server/routers/main_router.py b/strictdoc/server/routers/main_router.py
index 2694c8d07..19ac81c70 100644
--- a/strictdoc/server/routers/main_router.py
+++ b/strictdoc/server/routers/main_router.py
@@ -1035,7 +1035,9 @@ def __init__(self):
         for reference_field in form_object.reference_fields:
             ref_uid = reference_field.field_value
             references.append(
-                ParentReqReference(parent=requirement, ref_uid=ref_uid)
+                ParentReqReference(
+                    parent=requirement, ref_uid=ref_uid, relation_uid=None
+                )
             )
         if len(references) > 0:
             requirement.ordered_fields_lookup[RequirementFieldName.REFS] = [
diff --git a/tests/unit/helpers/test_document_builder.py b/tests/unit/helpers/test_document_builder.py
index 05c4c1d1a..6b83e667a 100644
--- a/tests/unit/helpers/test_document_builder.py
+++ b/tests/unit/helpers/test_document_builder.py
@@ -46,7 +46,9 @@ def add_requirement_parent(self, req_id, parent_req_id):
         )
         assert requirement
 
-        reference = ParentReqReference(requirement, parent_req_id)
+        reference = ParentReqReference(
+            requirement, parent_req_id, relation_uid=None
+        )
         requirement.references.append(reference)
 
     def build(self):
diff --git a/tests/unit/strictdoc/backend/sdoc/test_dsl_passthrough.py b/tests/unit/strictdoc/backend/sdoc/test_dsl_passthrough.py
index a901842fa..42546cb6a 100644
--- a/tests/unit/strictdoc/backend/sdoc/test_dsl_passthrough.py
+++ b/tests/unit/strictdoc/backend/sdoc/test_dsl_passthrough.py
@@ -151,6 +151,32 @@ def test_010_multiple_sections():
     assert input_sdoc == output
 
 
+def test_020_parent_ref_with_relation():
+    input_sdoc = """
+[DOCUMENT]
+TITLE: Test Doc
+
+[REQUIREMENT]
+REFS:
+- TYPE: Parent
+  VALUE: ID-001
+  RELATION: Refines
+STATEMENT: >>>
+This is a statement.
+<<<
+""".lstrip()
+
+    reader = SDReader()
+
+    document = reader.read(input_sdoc)
+    assert isinstance(document, Document)
+
+    writer = SDWriter()
+    output = writer.write(document)
+
+    assert input_sdoc == output
+
+
 def test_030_multiline_statement():
     input_sdoc = """
 [DOCUMENT]