diff --git a/slice/string.go b/slice/string.go
index 02bbacd0..21b983bc 100644
--- a/slice/string.go
+++ b/slice/string.go
@@ -1,5 +1,7 @@
 package slice
 
+import "strings"
+
 // ContainsString checks if a given slice of strings contains the provided string.
 // If a modifier func is provided, it is called with the slice item before the comparation.
 //      haystack := []string{"one", "Two", "Three"}
@@ -17,3 +19,19 @@ func ContainsString(s string, slice []string, modifier func(s string) string) bo
 	}
 	return false
 }
+
+// ContainsStringEqualFold checks if a given slice of strings contains the provided string
+// as ignore the cases.
+//
+//  haystack := []string{"aa", "bb", "Cc"}
+//	if slice.ContainsStringEqualFold(haystack, "cC") {
+//		// Do thing
+// 	}
+func ContainsStringEqualFold(s string, slice []string) bool {
+	for _, item := range slice {
+		if strings.EqualFold(item, s) {
+			return true
+		}
+	}
+	return false
+}
diff --git a/slice/string_test.go b/slice/string_test.go
new file mode 100644
index 00000000..e187ac09
--- /dev/null
+++ b/slice/string_test.go
@@ -0,0 +1,102 @@
+package slice_test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/mailgun/holster/slice"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestContainsString(t *testing.T) {
+	tests := []struct {
+		name     string
+		slice    []string
+		str      string
+		modifier func(string) string
+		want     bool
+	}{
+		{
+			name:     "Slice contains a specific string",
+			slice:    []string{"aa", "bb", "CC"},
+			modifier: strings.ToLower,
+			str:      "CC",
+			want:     true,
+		},
+		{
+			name:  "Slice contains a string, but it is with upper cases and modifier is nil",
+			slice: []string{"aa", "bb", "CC"},
+			str:   "cc",
+			want:  false,
+		},
+		{
+			name:     "Slice contains a string with upper cases and modifier ToLower is provided",
+			slice:    []string{"AA", "bb", "cc"},
+			modifier: strings.ToLower,
+			str:      "aa",
+			want:     true,
+		},
+		{
+			name:  "Slice does not contains string",
+			slice: []string{"AA", "bb", "cc"},
+			str:   "notExist",
+			want:  false,
+		},
+		{
+			name:  "Empty slice",
+			slice: []string{},
+			str:   "notExist",
+			want:  false,
+		},
+	}
+
+	for _, tt := range tests {
+		got := slice.ContainsString(tt.str, tt.slice, tt.modifier)
+		assert.Equal(t, tt.want, got)
+	}
+}
+
+func TestContainsStringIgnoreCase(t *testing.T) {
+	tests := []struct {
+		name  string
+		slice []string
+		str   string
+		want  bool
+	}{
+		{
+			name:  "Slice contains a specific string, but with different upper case",
+			slice: []string{"aa", "bb", "cC"},
+			str:   "Cc",
+			want:  true,
+		},
+		{
+			name:  "Slice contains a string, but it is with upper case",
+			slice: []string{"aa", "bb", "CC"},
+			str:   "cc",
+			want:  true,
+		},
+		{
+			name:  "Slice contains a string, but it is with lower cases",
+			slice: []string{"aa", "bb", "cc"},
+			str:   "AA",
+			want:  true,
+		},
+		{
+			name:  "Slice does not contains string",
+			slice: []string{"AA", "bb", "cc"},
+			str:   "notExist",
+			want:  false,
+		},
+		{
+			name:  "Empty slice",
+			slice: []string{},
+			str:   "notExist",
+			want:  false,
+		},
+	}
+
+	for _, tt := range tests {
+		got := slice.ContainsStringEqualFold(tt.str, tt.slice)
+		assert.Equal(t, tt.want, got)
+	}
+}