diff --git a/pkg/s3select/csv/errors.go b/pkg/s3select/csv/errors.go
index b01a448d9..eba0cbe1f 100644
--- a/pkg/s3select/csv/errors.go
+++ b/pkg/s3select/csv/errors.go
@@ -16,6 +16,8 @@
 
 package csv
 
+import "errors"
+
 type s3Error struct {
 	code       string
 	message    string
@@ -51,3 +53,12 @@ func errCSVParsingError(err error) *s3Error {
 		cause:      err,
 	}
 }
+
+func errInvalidTextEncodingError() *s3Error {
+	return &s3Error{
+		code:       "InvalidTextEncoding",
+		message:    "UTF-8 encoding is required.",
+		statusCode: 400,
+		cause:      errors.New("invalid utf8 encoding"),
+	}
+}
diff --git a/pkg/s3select/csv/reader.go b/pkg/s3select/csv/reader.go
index 84b5deeb9..12bedfdf2 100644
--- a/pkg/s3select/csv/reader.go
+++ b/pkg/s3select/csv/reader.go
@@ -23,6 +23,7 @@ import (
 	"io"
 	"runtime"
 	"sync"
+	"unicode/utf8"
 
 	csv "github.com/minio/minio/pkg/csvparser"
 	"github.com/minio/minio/pkg/s3select/sql"
@@ -159,6 +160,9 @@ func (r *Reader) startReaders(newReader func(io.Reader) *csv.Reader) error {
 			r.err = err
 			return err
 		}
+		if !utf8.Valid(b) {
+			return errInvalidTextEncodingError()
+		}
 		reader := newReader(bytes.NewReader(b))
 		record, err := reader.Read()
 		if err != nil {
@@ -181,6 +185,13 @@ func (r *Reader) startReaders(newReader func(io.Reader) *csv.Reader) error {
 		return make([]byte, csvSplitSize+1024)
 	}
 
+	// Return first block
+	next, nextErr := r.nextSplit(csvSplitSize, r.bufferPool.Get().([]byte))
+	// Check if first block is valid.
+	if !utf8.Valid(next) {
+		return errInvalidTextEncodingError()
+	}
+
 	// Create queue
 	r.queue = make(chan *queueItem, runtime.GOMAXPROCS(0))
 	r.input = make(chan *queueItem, runtime.GOMAXPROCS(0))
@@ -192,11 +203,10 @@ func (r *Reader) startReaders(newReader func(io.Reader) *csv.Reader) error {
 		defer close(r.queue)
 		defer r.readerWg.Done()
 		for {
-			next, err := r.nextSplit(csvSplitSize, r.bufferPool.Get().([]byte))
 			q := queueItem{
 				input: next,
 				dst:   make(chan [][]string, 1),
-				err:   err,
+				err:   nextErr,
 			}
 			select {
 			case <-r.close:
@@ -209,10 +219,11 @@ func (r *Reader) startReaders(newReader func(io.Reader) *csv.Reader) error {
 				return
 			case r.input <- &q:
 			}
-			if err != nil {
+			if nextErr != nil {
 				// Exit on any error.
 				return
 			}
+			next, nextErr = r.nextSplit(csvSplitSize, r.bufferPool.Get().([]byte))
 		}
 	}()