diff --git a/encoder.go b/encoder.go
index b92ef42..39c84f7 100644
--- a/encoder.go
+++ b/encoder.go
@@ -36,7 +36,16 @@ func newXMLEncoder(w io.Writer, floatPresicion int) *xmlEncoder {
 // AddRelationship adds a relationship to the encoded model.
 // Duplicated relationships will be removed before encoding.
 func (enc *xmlEncoder) AddRelationship(r spec.Relationship) {
-	enc.relationships = append(enc.relationships, Relationship(r))
+	hasRelationship := false
+	for _, relationship := range enc.relationships {
+		if relationship.Path == r.Path {
+			hasRelationship = true
+			break
+		}
+	}
+	if !hasRelationship {
+		enc.relationships = append(enc.relationships, Relationship(r))
+	}
 }
 
 // FloatPresicion returns the float presicion to use
diff --git a/encoder_test.go b/encoder_test.go
index 98a2510..a0b8b2e 100644
--- a/encoder_test.go
+++ b/encoder_test.go
@@ -8,12 +8,14 @@ import (
 	"encoding/xml"
 	"errors"
 	"image/color"
+	"path/filepath"
 	"reflect"
 	"strconv"
 	"testing"
 
 	"github.com/go-test/deep"
 	"github.com/hpinc/go3mf/spec"
+	"github.com/hpinc/go3mf/utils"
 	"github.com/stretchr/testify/mock"
 )
 
@@ -309,3 +311,62 @@ func TestEncoder_Encode_Roundtrip(t *testing.T) {
 		})
 	}
 }
+
+func TestEncoder_Relationship(t *testing.T) {
+	type request struct {
+		fileName string
+	}
+	type response struct {
+		relationships []Relationship
+	}
+
+	tests := []struct {
+		name     string
+		request  request
+		response response
+	}{ /*Verfy if a file rels is not update in case of relationship exists*/
+		{"file_with_texture_rel_but_no_texture",
+			request{fileName: "super_boogoku_tiny.3mf"},
+			response{relationships: []Relationship{
+				{ID: "rel2", Type: "http://schemas.microsoft.com/3dmanufacturing/2013/01/3dtexture", Path: "/Thumbnails/super_boo.png"},
+				{ID: "rel3", Type: "http://schemas.microsoft.com/3dmanufacturing/2013/01/3dtexture", Path: "/Thumbnails/goku_ss.png"},
+			}},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			utils.WithProjectDirAndTestTempDirRemoveAtEnd(
+				filepath.Join("testdata"), func(testFileDir string, testTempDir string) {
+					testFile := filepath.Join(testFileDir, tt.request.fileName)
+					outputFile := filepath.Join(testTempDir, "SW3DBUG-2700_changed.3mf")
+					var model Model
+					r, err := OpenReader(testFile)
+					if err != nil {
+						t.Errorf("TestEncoder_Relationship() error = %v", err)
+					}
+					r.Decode(&model)
+					defer r.Close()
+					w, err := CreateWriter(outputFile)
+					if err != nil {
+						t.Errorf("TestEncoder_Relationship() error = %v", err)
+					}
+					w.Encode(&model)
+					defer w.Close()
+
+					var modelUpdated Model
+					r, err = OpenReader(outputFile)
+					if err != nil {
+						t.Errorf("TestEncoder_Relationship() error = %v", err)
+					}
+					r.Decode(&modelUpdated)
+					defer r.Close()
+
+					if diff := deep.Equal(modelUpdated.Relationships, tt.response.relationships); diff != nil {
+						t.Errorf("TestEncoder_Relationship() = %v", diff)
+					}
+				})
+
+		})
+	}
+
+}
diff --git a/testdata/super_boogoku_tiny.3mf b/testdata/super_boogoku_tiny.3mf
new file mode 100644
index 0000000..10b31ae
Binary files /dev/null and b/testdata/super_boogoku_tiny.3mf differ
diff --git a/utils/utils.go b/utils/utils.go
new file mode 100644
index 0000000..8988e19
--- /dev/null
+++ b/utils/utils.go
@@ -0,0 +1,39 @@
+package utils
+
+import (
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"runtime"
+)
+
+func GetRootProjectDir() (string, error) {
+	_, filename, _, _ := runtime.Caller(0)
+	dir := filepath.Join(path.Dir(filename), "..")
+	err := os.Chdir(dir)
+	return dir, err
+}
+
+func WithRootProjectDir(callback func(string)) {
+	dir, err := GetRootProjectDir()
+	if err != nil {
+		panic(err)
+	}
+	callback(dir)
+}
+
+func WithProjectDirAndTestTempDirRemoveAtEnd(fileFolder string, callback func(testFileDir string, testTempDir string)) {
+	dir, err := GetRootProjectDir()
+	if err != nil {
+		panic(err)
+	}
+	testTempDir, err := ioutil.TempDir("", "testcase")
+	if err != nil {
+		panic(err)
+	}
+	defer os.RemoveAll(testTempDir)
+	defer os.Remove(testTempDir)
+
+	callback(filepath.Join(dir, fileFolder), testTempDir)
+}