diff --git a/CHANGELOG.md b/CHANGELOG.md
index 85450122a9..e6b49139e4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 
 ### Fixed
 
+- [#4468](https://github.com/thanos-io/thanos/pull/4468) Rule: Fix temporary rule filename composition issue.
 - [#4476](https://github.com/thanos-io/thanos/pull/4476) UI: fix incorrect html escape sequence used for '>' symbol.
 
 ### Changed
diff --git a/pkg/rules/manager.go b/pkg/rules/manager.go
index b671abb207..d2500205bc 100644
--- a/pkg/rules/manager.go
+++ b/pkg/rules/manager.go
@@ -356,7 +356,7 @@ func (m *Manager) Update(evalInterval time.Duration, files []string) error {
 
 			// Use full file name appending to work dir, so we can differentiate between different dirs and same filenames(!).
 			// This will be also used as key for file group name.
-			newFn := filepath.Join(m.workDir, s.String(), strings.TrimLeft(fn, m.workDir))
+			newFn := filepath.Join(m.workDir, s.String(), fn)
 			if err := os.MkdirAll(filepath.Dir(newFn), os.ModePerm); err != nil {
 				errs.Add(errors.Wrapf(err, "create %s", filepath.Dir(newFn)))
 				continue
diff --git a/pkg/rules/manager_test.go b/pkg/rules/manager_test.go
index d4230da74c..288abe729a 100644
--- a/pkg/rules/manager_test.go
+++ b/pkg/rules/manager_test.go
@@ -106,7 +106,12 @@ groups:
 func TestUpdate_Error_UpdatePartial(t *testing.T) {
 	dir, err := ioutil.TempDir("", "test_rule_rule_groups")
 	testutil.Ok(t, err)
-	defer func() { testutil.Ok(t, os.RemoveAll(dir)) }()
+	dataDir, err := ioutil.TempDir("", "test_rule_data")
+	testutil.Ok(t, err)
+	defer func() {
+		testutil.Ok(t, os.RemoveAll(dir))
+		testutil.Ok(t, os.RemoveAll(dataDir))
+	}()
 	err = os.MkdirAll(filepath.Join(dir, "subdir"), 0775)
 	testutil.Ok(t, err)
 
@@ -171,7 +176,7 @@ groups:
 	thanosRuleMgr := NewManager(
 		context.Background(),
 		reg,
-		dir,
+		dataDir,
 		rules.ManagerOptions{
 			Logger:    log.NewLogfmtLogger(os.Stderr),
 			Queryable: nopQueryable{},
@@ -200,13 +205,13 @@ groups:
 	// Also, check metrics: Regression test: https://github.com/thanos-io/thanos/issues/3083
 	testutil.Equals(t,
 		map[string]float64{
-			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/ABORT/abort.yaml;something2,strategy=abort}", dir):            1,
-			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/ABORT/bdir/no_strategy.yaml;something8,strategy=abort}", dir): 1,
-			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/ABORT/combined.yaml;something6,strategy=abort}", dir):         1,
-			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/ABORT/combined.yaml;something7,strategy=abort}", dir):         1,
-			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/ABORT/no_strategy.yaml;something1,strategy=abort}", dir):      1,
-			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/WARN/combined.yaml;something5,strategy=warn}", dir):           1,
-			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/WARN/warn.yaml;something3,strategy=warn}", dir):               1,
+			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/ABORT%s/abort.yaml;something2,strategy=abort}", dataDir, dir):              1,
+			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/ABORT%s/subdir/no_strategy.yaml;something8,strategy=abort}", dataDir, dir): 1,
+			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/ABORT%s/combined.yaml;something6,strategy=abort}", dataDir, dir):           1,
+			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/ABORT%s/combined.yaml;something7,strategy=abort}", dataDir, dir):           1,
+			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/ABORT%s/no_strategy.yaml;something1,strategy=abort}", dataDir, dir):        1,
+			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/WARN%s/combined.yaml;something5,strategy=warn}", dataDir, dir):             1,
+			fmt.Sprintf("prometheus_rule_group_rules{rule_group=%s/.tmp-rules/WARN%s/warn.yaml;something3,strategy=warn}", dataDir, dir):                 1,
 		},
 		extprom.CurrentGaugeValuesFor(t, reg, "prometheus_rule_group_rules"),
 	)