diff --git a/core.d.ts b/core.d.ts
index 11d0506b..e234094a 100644
--- a/core.d.ts
+++ b/core.d.ts
@@ -353,7 +353,7 @@ declare namespace core {
 	/**
 	Supported MIME types.
 	*/
-	const mimeTypes: readonly core.MimeType[];
+	const mimeTypes: Set<core.MimeType>;
 
 	/**
 	Detect the file type of a readable stream.
diff --git a/index.test-d.ts b/index.test-d.ts
index 8fc852f7..6cf082cd 100644
--- a/index.test-d.ts
+++ b/index.test-d.ts
@@ -41,7 +41,7 @@ expectType<Promise<FileTypeResult | undefined>>(FileType.fromBuffer(new ArrayBuf
 
 expectType<Set<FileType.FileExtension>>(FileType.extensions);
 
-expectType<readonly FileType.MimeType[]>(FileType.mimeTypes);
+expectType<Set<FileType.MimeType>>(FileType.mimeTypes);
 
 const readableStream = fs.createReadStream('file.png');
 const streamWithFileType = FileType.stream(readableStream);