diff --git a/icu4c/data/convrtrs.txt b/icu4c/data/convrtrs.txt
index 475a0b68ae..60da6d9415 100644
--- a/icu4c/data/convrtrs.txt
+++ b/icu4c/data/convrtrs.txt
@@ -154,6 +154,8 @@ ibm-1283                maccy                   # Apple Cyrillic
 
 ibm-1051                hp-roman8 roman8 r8 csHPRoman8  # HP Latin1
 
+ibm-1388                #MBCS
+
 # Added for more euro support
 
 ibm-849                cp1131          # PC Belarus (w/ euro update)
diff --git a/icu4c/source/data/mappings/convrtrs.txt b/icu4c/source/data/mappings/convrtrs.txt
index 475a0b68ae..60da6d9415 100644
--- a/icu4c/source/data/mappings/convrtrs.txt
+++ b/icu4c/source/data/mappings/convrtrs.txt
@@ -154,6 +154,8 @@ ibm-1283                maccy                   # Apple Cyrillic
 
 ibm-1051                hp-roman8 roman8 r8 csHPRoman8  # HP Latin1
 
+ibm-1388                #MBCS
+
 # Added for more euro support
 
 ibm-849                cp1131          # PC Belarus (w/ euro update)