diff --git a/csl/chicago-fullnote-bibliography.csl b/csl/chicago-fullnote-bibliography.csl
index 48d852c58e..a35322ff79 100644
--- a/csl/chicago-fullnote-bibliography.csl
+++ b/csl/chicago-fullnote-bibliography.csl
@@ -523,7 +523,6 @@
     <option name="et-al-use-first" value="1"/>
     <option name="et-al-subsequent-min" value="4"/>
     <option name="et-al-subsequent-use-first" value="1"/>
-    <option name="disambiguate-add-year-suffix" value="true"/>
     <option name="disambiguate-add-names" value="true"/>
     <option name="disambiguate-add-givenname" value="true"/>
     <layout prefix="" suffix="." delimiter="; ">
diff --git a/csl/chicago-note-bibliography.csl b/csl/chicago-note-bibliography.csl
index 3bf48da899..450f0ec9e6 100644
--- a/csl/chicago-note-bibliography.csl
+++ b/csl/chicago-note-bibliography.csl
@@ -352,7 +352,6 @@
     <option name="et-al-use-first" value="1"/>
     <option name="et-al-subsequent-min" value="4"/>
     <option name="et-al-subsequent-use-first" value="1"/>
-    <option name="disambiguate-add-year-suffix" value="true"/>
     <option name="disambiguate-add-names" value="true"/>
     <option name="disambiguate-add-givenname" value="true"/>
     <layout prefix="" suffix="." delimiter="; ">
diff --git a/csl/chicago-note-no-ibid.csl b/csl/chicago-note-no-ibid.csl
index d893b1e4bc..14ed002141 100644
--- a/csl/chicago-note-no-ibid.csl
+++ b/csl/chicago-note-no-ibid.csl
@@ -296,7 +296,6 @@
     <option name="et-al-use-first" value="1"/>
     <option name="et-al-subsequent-min" value="4"/>
     <option name="et-al-subsequent-use-first" value="1"/>
-    <option name="disambiguate-add-year-suffix" value="true"/>
     <option name="disambiguate-add-names" value="true"/>
     <option name="disambiguate-add-givenname" value="true"/>
     <layout prefix="" suffix="." delimiter="; ">
diff --git a/csl/chicago-note.csl b/csl/chicago-note.csl
index 634d166783..b46db9d81b 100644
--- a/csl/chicago-note.csl
+++ b/csl/chicago-note.csl
@@ -296,7 +296,6 @@
     <option name="et-al-use-first" value="1"/>
     <option name="et-al-subsequent-min" value="4"/>
     <option name="et-al-subsequent-use-first" value="1"/>
-    <option name="disambiguate-add-year-suffix" value="true"/>
     <option name="disambiguate-add-names" value="true"/>
     <option name="disambiguate-add-givenname" value="true"/>
     <layout prefix="" suffix="." delimiter="; ">