diff --git a/components/ledger/internal/storage/ledgerstore/bucket.go b/components/ledger/internal/storage/ledgerstore/bucket.go
index 703e93fd87..09fdab81cb 100644
--- a/components/ledger/internal/storage/ledgerstore/bucket.go
+++ b/components/ledger/internal/storage/ledgerstore/bucket.go
@@ -41,6 +41,9 @@ var addIndexOnReference string
 //go:embed migrations/7-add-ik-unique-index.sql
 var addIKUniqueIndex string
 
+//go:embed migrations/8-ik-ledger-unique-index.sql
+var updateIKUniqueIndex string
+
 type Bucket struct {
 	name string
 	db   *bun.DB
@@ -200,6 +203,13 @@ func registerMigrations(migrator *migrations.Migrator, name string) {
 				return err
 			},
 		},
+		migrations.Migration{
+			Name: "Update unique index on IK",
+			UpWithContext: func(ctx context.Context, tx bun.Tx) error {
+				_, err := tx.ExecContext(ctx, updateIKUniqueIndex)
+				return err
+			},
+		},
 	)
 }
 
diff --git a/components/ledger/internal/storage/ledgerstore/migrations/8-ik-ledger-unique-index.sql b/components/ledger/internal/storage/ledgerstore/migrations/8-ik-ledger-unique-index.sql
new file mode 100644
index 0000000000..1093bf9c01
--- /dev/null
+++ b/components/ledger/internal/storage/ledgerstore/migrations/8-ik-ledger-unique-index.sql
@@ -0,0 +1,3 @@
+drop index logs_idempotency_key;
+
+create unique index logs_idempotency_key on logs (ledger, idempotency_key);
\ No newline at end of file
diff --git a/tests/integration/suite/ledger-create-transaction-ik.go b/tests/integration/suite/ledger-create-transaction-ik.go
new file mode 100644
index 0000000000..ba626bb329
--- /dev/null
+++ b/tests/integration/suite/ledger-create-transaction-ik.go
@@ -0,0 +1,86 @@
+package suite
+
+import (
+	"math/big"
+	"net/http"
+	"time"
+
+	"github.com/formancehq/stack/tests/integration/internal/modules"
+
+	"github.com/formancehq/formance-sdk-go/v2/pkg/models/operations"
+	"github.com/formancehq/formance-sdk-go/v2/pkg/models/shared"
+	"github.com/formancehq/stack/libs/go-libs/pointer"
+	. "github.com/formancehq/stack/tests/integration/internal"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = WithModules([]*Module{modules.Search, modules.Ledger}, func() {
+	BeforeEach(func() {
+		createLedgerResponse, err := Client().Ledger.V2CreateLedger(TestContext(), operations.V2CreateLedgerRequest{
+			Ledger: "default",
+		})
+		Expect(err).To(BeNil())
+		Expect(createLedgerResponse.StatusCode).To(Equal(http.StatusNoContent))
+
+		createLedgerResponse, err = Client().Ledger.V2CreateLedger(TestContext(), operations.V2CreateLedgerRequest{
+			Ledger: "test",
+		})
+		Expect(err).To(BeNil())
+		Expect(createLedgerResponse.StatusCode).To(Equal(http.StatusNoContent))
+	})
+	When("creating a transaction on a ledger", func() {
+		var (
+			timestamp  = time.Now().Add(-1 * time.Minute).Round(time.Second).UTC()
+			timestamp2 = time.Now().Round(time.Second).UTC()
+		)
+		It("should fail", func() {
+			// Create a transaction
+			response, err := Client().Ledger.V2CreateTransaction(
+				TestContext(),
+				operations.V2CreateTransactionRequest{
+					IdempotencyKey: pointer.For("foo"),
+					V2PostTransaction: shared.V2PostTransaction{
+						Metadata: map[string]string{},
+						Postings: []shared.V2Posting{
+							{
+								Amount:      big.NewInt(100),
+								Asset:       "USD",
+								Source:      "world",
+								Destination: "alice",
+							},
+						},
+						Timestamp: &timestamp,
+						Reference: pointer.For("foo"),
+					},
+					Ledger: "default",
+				},
+			)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(response.StatusCode).To(Equal(200))
+
+			response, err = Client().Ledger.V2CreateTransaction(
+				TestContext(),
+				operations.V2CreateTransactionRequest{
+					IdempotencyKey: pointer.For("foo"),
+					V2PostTransaction: shared.V2PostTransaction{
+						Metadata: map[string]string{},
+						Postings: []shared.V2Posting{
+							{
+								Amount:      big.NewInt(100),
+								Asset:       "USD",
+								Source:      "world",
+								Destination: "alice",
+							},
+						},
+						Timestamp: &timestamp2,
+						Reference: pointer.For("foo2"),
+					},
+					Ledger: "test",
+				},
+			)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(response.StatusCode).To(Equal(200))
+		})
+	})
+})