diff --git a/s3store/s3store.go b/s3store/s3store.go
index 0980bf4..7b467e6 100644
--- a/s3store/s3store.go
+++ b/s3store/s3store.go
@@ -31,7 +31,13 @@
 //
 // If meta data is associated with the upload during creation, it will be added
 // to the multipart upload and after finishing it, the meta data will be passed
-// to the final object.
+// to the final object. However, the metadata which will be attached to the
+// final object can only contain ASCII characters and every non-ASCII character
+// will be replaced by a question mark (for example, "Menü" will be "Men?").
+// However, this does not apply for the metadata returned by the GetInfo
+// function since it relies on the info object for reading the metadata.
+// Therefore, HEAD responses will always contain the unchanged metadata, Base64-
+// encoded, even if it contains non-ASCII characters.
 //
 // Once the upload is finish, the multipart upload is completed, resulting in
 // the entire file being stored in the bucket. The info object, containing
@@ -81,6 +87,7 @@ import (
 	"io"
 	"io/ioutil"
 	"os"
+	"regexp"
 	"strings"
 	"sync"
 
@@ -93,6 +100,10 @@ import (
 	"github.com/aws/aws-sdk-go/service/s3/s3iface"
 )
 
+// This regular expression matches every character which is not defined in the
+// ASCII tables which range from 00 to 7F, inclusive.
+var nonASCIIRegexp = regexp.MustCompile(`([^\x00-\x7F])`)
+
 // See the tusd.DataStore interface for documentation about the different
 // methods.
 type S3Store struct {
@@ -162,7 +173,7 @@ func (store S3Store) NewUpload(info tusd.FileInfo) (id string, err error) {
 		ContentLength: aws.Int64(int64(len(infoJson))),
 	})
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("s3store: unable to create info file:\n%s", err)
 	}
 
 	// Convert meta data into a map of pointers for AWS Go SDK, sigh.
@@ -170,7 +181,7 @@ func (store S3Store) NewUpload(info tusd.FileInfo) (id string, err error) {
 	for key, value := range info.MetaData {
 		// Copying the value is required in order to prevent it from being
 		// overwritten by the next iteration.
-		v := value
+		v := nonASCIIRegexp.ReplaceAllString(value, "?")
 		metadata[key] = &v
 	}
 
@@ -181,7 +192,7 @@ func (store S3Store) NewUpload(info tusd.FileInfo) (id string, err error) {
 		Metadata: metadata,
 	})
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("s3store: unable to create multipart upload:\n%s", err)
 	}
 
 	id = uploadId + "+" + *res.UploadId
diff --git a/s3store/s3store_test.go b/s3store/s3store_test.go
index c77b13f..de45129 100644
--- a/s3store/s3store_test.go
+++ b/s3store/s3store_test.go
@@ -36,13 +36,13 @@ func TestNewUpload(t *testing.T) {
 	assert.Equal(store.Service, s3obj)
 
 	s1 := "hello"
-	s2 := "world"
+	s2 := "men?"
 
 	gomock.InOrder(
 		s3obj.EXPECT().PutObject(&s3.PutObjectInput{
 			Bucket:        aws.String("bucket"),
 			Key:           aws.String("uploadId.info"),
-			Body:          bytes.NewReader([]byte(`{"ID":"uploadId","Size":500,"Offset":0,"MetaData":{"bar":"world","foo":"hello"},"IsPartial":false,"IsFinal":false,"PartialUploads":null}`)),
+			Body:          bytes.NewReader([]byte(`{"ID":"uploadId","Size":500,"Offset":0,"MetaData":{"bar":"menü","foo":"hello"},"IsPartial":false,"IsFinal":false,"PartialUploads":null}`)),
 			ContentLength: aws.Int64(int64(136)),
 		}),
 		s3obj.EXPECT().CreateMultipartUpload(&s3.CreateMultipartUploadInput{
@@ -62,7 +62,7 @@ func TestNewUpload(t *testing.T) {
 		Size: 500,
 		MetaData: map[string]string{
 			"foo": "hello",
-			"bar": "world",
+			"bar": "menü",
 		},
 	}
 
@@ -101,7 +101,7 @@ func TestGetInfo(t *testing.T) {
 			Bucket: aws.String("bucket"),
 			Key:    aws.String("uploadId.info"),
 		}).Return(&s3.GetObjectOutput{
-			Body: ioutil.NopCloser(bytes.NewReader([]byte(`{"ID":"uploadId","Size":500,"Offset":0,"MetaData":null,"IsPartial":false,"IsFinal":false,"PartialUploads":null}`))),
+			Body: ioutil.NopCloser(bytes.NewReader([]byte(`{"ID":"uploadId","Size":500,"Offset":0,"MetaData":{"bar":"menü","foo":"hello"},"IsPartial":false,"IsFinal":false,"PartialUploads":null}`))),
 		}, nil),
 		s3obj.EXPECT().ListParts(&s3.ListPartsInput{
 			Bucket:   aws.String("bucket"),
@@ -124,6 +124,8 @@ func TestGetInfo(t *testing.T) {
 	assert.Equal(int64(500), info.Size)
 	assert.Equal(int64(300), info.Offset)
 	assert.Equal("uploadId+multipartId", info.ID)
+	assert.Equal("hello", info.MetaData["foo"])
+	assert.Equal("menü", info.MetaData["bar"])
 }
 
 func TestGetInfoFinished(t *testing.T) {