diff --git a/Tests/LibWeb/TestFetchURL.cpp b/Tests/LibWeb/TestFetchURL.cpp
index 590fe9fd7e..737f114f21 100644
--- a/Tests/LibWeb/TestFetchURL.cpp
+++ b/Tests/LibWeb/TestFetchURL.cpp
@@ -18,7 +18,7 @@ TEST_CASE(data_url)
     EXPECT_EQ(url.serialize(), "data:text/html,test");
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
-    EXPECT_EQ(data_url.mime_type, "text/html");
+    EXPECT_EQ(TRY_OR_FAIL(data_url.mime_type.serialized()), "text/html");
     EXPECT_EQ(StringView(data_url.body.bytes()), "test"sv);
 }
 
@@ -31,7 +31,7 @@ TEST_CASE(data_url_default_mime_type)
     EXPECT_EQ(url.serialize(), "data:,test");
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
-    EXPECT_EQ(data_url.mime_type, "text/plain;charset=US-ASCII");
+    EXPECT_EQ(TRY_OR_FAIL(data_url.mime_type.serialized()), "text/plain;charset=US-ASCII");
     EXPECT_EQ(StringView(data_url.body.bytes()), "test"sv);
 }
 
@@ -44,7 +44,7 @@ TEST_CASE(data_url_encoded)
     EXPECT_EQ(url.serialize(), "data:text/html,Hello%20friends%2C%0X%X0");
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
-    EXPECT_EQ(data_url.mime_type, "text/html");
+    EXPECT_EQ(TRY_OR_FAIL(data_url.mime_type.serialized()), "text/html");
     EXPECT_EQ(StringView(data_url.body.bytes()), "Hello friends,%0X%X0"sv);
 }
 
@@ -57,7 +57,7 @@ TEST_CASE(data_url_base64_encoded)
     EXPECT_EQ(url.serialize(), "data:text/html;base64,dGVzdA==");
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
-    EXPECT_EQ(data_url.mime_type, "text/html");
+    EXPECT_EQ(TRY_OR_FAIL(data_url.mime_type.serialized()), "text/html");
     EXPECT_EQ(StringView(data_url.body.bytes()), "test"sv);
 }
 
@@ -70,7 +70,7 @@ TEST_CASE(data_url_base64_encoded_default_mime_type)
     EXPECT_EQ(url.serialize(), "data:;base64,dGVzdA==");
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
-    EXPECT_EQ(data_url.mime_type, "text/plain;charset=US-ASCII");
+    EXPECT_EQ(TRY_OR_FAIL(data_url.mime_type.serialized()), "text/plain;charset=US-ASCII");
     EXPECT_EQ(StringView(data_url.body.bytes()), "test"sv);
 }
 
@@ -83,7 +83,7 @@ TEST_CASE(data_url_base64_encoded_with_whitespace)
     EXPECT_EQ(url.serialize(), "data: text/html ;     bAsE64 , dGVz dA==");
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
-    EXPECT_EQ(data_url.mime_type, "text/html");
+    EXPECT_EQ(TRY_OR_FAIL(data_url.mime_type.serialized()), "text/html");
     EXPECT_EQ(StringView(data_url.body.bytes()), "test");
 }
 
@@ -95,7 +95,7 @@ TEST_CASE(data_url_base64_encoded_with_inline_whitespace)
     EXPECT(url.host().has<Empty>());
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
-    EXPECT_EQ(data_url.mime_type, "text/javascript");
+    EXPECT_EQ(TRY_OR_FAIL(data_url.mime_type.serialized()), "text/javascript");
     EXPECT_EQ(StringView(data_url.body.bytes()), "d4 = 'four';"sv);
 }
 
@@ -108,6 +108,6 @@ TEST_CASE(data_url_completed_with_fragment)
     EXPECT(url.host().has<Empty>());
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
-    EXPECT_EQ(data_url.mime_type, "text/plain");
+    EXPECT_EQ(TRY_OR_FAIL(data_url.mime_type.serialized()), "text/plain");
     EXPECT_EQ(StringView(data_url.body.bytes()), "test"sv);
 }
diff --git a/Userland/Libraries/LibWeb/Fetch/Fetching/Fetching.cpp b/Userland/Libraries/LibWeb/Fetch/Fetching/Fetching.cpp
index cddb12841c..13b58caf9a 100644
--- a/Userland/Libraries/LibWeb/Fetch/Fetching/Fetching.cpp
+++ b/Userland/Libraries/LibWeb/Fetch/Fetching/Fetching.cpp
@@ -851,8 +851,7 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<PendingResponse>> scheme_fetch(JS::Realm& r
             return PendingResponse::create(vm, request, Infrastructure::Response::network_error(vm, "Failed to process 'data:' URL"sv));
 
         // 3. Let mimeType be dataURLStruct’s MIME type, serialized.
-        //    FIXME: Serialize MIME type.
-        auto const& mime_type = data_url_struct.value().mime_type;
+        auto const& mime_type = MUST(data_url_struct.value().mime_type.serialized());
 
         // 4. Return a new response whose status message is `OK`, header list is « (`Content-Type`, mimeType) », and
         //    body is dataURLStruct’s body as a body.
diff --git a/Userland/Libraries/LibWeb/Fetch/Infrastructure/URL.cpp b/Userland/Libraries/LibWeb/Fetch/Infrastructure/URL.cpp
index 51f00a8108..47c3533f33 100644
--- a/Userland/Libraries/LibWeb/Fetch/Infrastructure/URL.cpp
+++ b/Userland/Libraries/LibWeb/Fetch/Infrastructure/URL.cpp
@@ -8,6 +8,7 @@
 
 #include <LibURL/URL.h>
 #include <LibWeb/Fetch/Infrastructure/URL.h>
+#include <LibWeb/MimeSniff/MimeType.h>
 #include <Userland/Libraries/LibWeb/Infra/Base64.h>
 
 namespace Web::Fetch::Infrastructure {
@@ -95,16 +96,17 @@ ErrorOr<DataURL> process_data_url(URL::URL const& data_url)
         mime_type = builder.string_view();
     }
 
-    // FIXME: Parse the MIME type's components according to https://mimesniff.spec.whatwg.org/#parse-a-mime-type
-    // FIXME: 13. Let mimeTypeRecord be the result of parsing mimeType.
-    auto mime_type_record = mime_type.trim("\n\r\t "sv, TrimMode::Both);
+    // 13. Let mimeTypeRecord be the result of parsing mimeType.
+    auto mime_type_record = TRY(MimeSniff::MimeType::parse(mime_type));
 
     // 14. If mimeTypeRecord is failure, then set mimeTypeRecord to text/plain;charset=US-ASCII.
-    if (mime_type_record.is_empty())
-        mime_type_record = "text/plain;charset=US-ASCII"sv;
+    if (!mime_type_record.has_value()) {
+        mime_type_record = TRY(MimeSniff::MimeType::create("text"_string, "plain"_string));
+        TRY(mime_type_record->set_parameter("charset"_string, "US-ASCII"_string));
+    }
 
     // 15. Return a new data: URL struct whose MIME type is mimeTypeRecord and body is body.
-    return DataURL { TRY(String::from_utf8(mime_type_record)), body };
+    return DataURL { mime_type_record.release_value(), body };
 }
 
 }
diff --git a/Userland/Libraries/LibWeb/Fetch/Infrastructure/URL.h b/Userland/Libraries/LibWeb/Fetch/Infrastructure/URL.h
index 0b6ea07731..b14c16dcd5 100644
--- a/Userland/Libraries/LibWeb/Fetch/Infrastructure/URL.h
+++ b/Userland/Libraries/LibWeb/Fetch/Infrastructure/URL.h
@@ -13,6 +13,7 @@
 #include <AK/String.h>
 #include <AK/StringView.h>
 #include <LibURL/Forward.h>
+#include <LibWeb/MimeSniff/MimeType.h>
 
 namespace Web::Fetch::Infrastructure {
 
@@ -39,7 +40,7 @@ inline constexpr Array FETCH_SCHEMES = {
 
 // https://fetch.spec.whatwg.org/#data-url-struct
 struct DataURL {
-    String mime_type;
+    MimeSniff::MimeType mime_type;
     ByteBuffer body;
 };
 
diff --git a/Userland/Libraries/LibWeb/Loader/ResourceLoader.cpp b/Userland/Libraries/LibWeb/Loader/ResourceLoader.cpp
index b08593a776..95d86e099c 100644
--- a/Userland/Libraries/LibWeb/Loader/ResourceLoader.cpp
+++ b/Userland/Libraries/LibWeb/Loader/ResourceLoader.cpp
@@ -301,11 +301,11 @@ void ResourceLoader::load(LoadRequest& request, SuccessCallback success_callback
         auto data_url = data_url_or_error.release_value();
 
         dbgln_if(SPAM_DEBUG, "ResourceLoader loading a data URL with mime-type: '{}', payload='{}'",
-            data_url.mime_type,
+            MUST(data_url.mime_type.serialized()),
             StringView(data_url.body.bytes()));
 
         HashMap<ByteString, ByteString, CaseInsensitiveStringTraits> response_headers;
-        response_headers.set("Content-Type", data_url.mime_type.to_byte_string());
+        response_headers.set("Content-Type", MUST(data_url.mime_type.serialized()).to_byte_string());
 
         log_success(request);