diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 188cf23f76c9c..139e078e2abe3 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1712,10 +1712,6 @@
         "category": "Error",
         "code": 2654
     },
-    "Exported external package typings can only be in '.d.ts' files. Please contact the package author to update the package definition.": {
-        "category": "Error",
-        "code": 2655
-    },
     "Exported external package typings file '{0}' is not a module. Please contact the package author to update the package definition.": {
         "category": "Error",
         "code": 2656
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index d76e7585d1541..d39a4c7912f8c 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -863,10 +863,6 @@ namespace ts {
                                 let start = getTokenPosOfNode(file.imports[i], file);
                                 fileProcessingDiagnostics.add(createFileDiagnostic(file, start, file.imports[i].end - start, Diagnostics.Exported_external_package_typings_file_0_is_not_a_module_Please_contact_the_package_author_to_update_the_package_definition, importedFile.fileName));
                             }
-                            else if (!fileExtensionIs(importedFile.fileName, ".d.ts")) {
-                                let start = getTokenPosOfNode(file.imports[i], file);
-                                fileProcessingDiagnostics.add(createFileDiagnostic(file, start, file.imports[i].end - start, Diagnostics.Exported_external_package_typings_can_only_be_in_d_ts_files_Please_contact_the_package_author_to_update_the_package_definition));
-                            }
                             else if (importedFile.referencedFiles.length) {
                                 let firstRef = importedFile.referencedFiles[0];
                                 fileProcessingDiagnostics.add(createFileDiagnostic(importedFile, firstRef.pos, firstRef.end - firstRef.pos, Diagnostics.Exported_external_package_typings_file_cannot_contain_tripleslash_references_Please_contact_the_package_author_to_update_the_package_definition));