diff --git a/backend/src/utils/tenantFullExport.ts b/backend/src/utils/tenantFullExport.ts
index 61ea64b..1fc4aeb 100644
--- a/backend/src/utils/tenantFullExport.ts
+++ b/backend/src/utils/tenantFullExport.ts
@@ -11,6 +11,7 @@ import { pool } from "../../db"
 import { s3 } from "./s3"
 import { secrets } from "./secrets"
 import { decrypt, encrypt } from "./crypt"
+import { restoreImportedTenantNumberRanges } from "./tenantImportNumberRanges"
 
 type TableRows = Record<string, Record<string, any>[]>
 type TableMetadata = {
@@ -991,6 +992,8 @@ export const importTenantFullExport = async (
         progressDone += 1
         await reportProgress("Kommunikationsräume bereinigt")
 
+        await restoreImportedTenantNumberRanges(client, exportData)
+
         await refreshSequences(client, columnsByTable)
         progressDone = progressTotal
         await reportProgress("Import abgeschlossen")
diff --git a/backend/src/utils/tenantImportNumberRanges.ts b/backend/src/utils/tenantImportNumberRanges.ts
new file mode 100644
index 0000000..fe348b5
--- /dev/null
+++ b/backend/src/utils/tenantImportNumberRanges.ts
@@ -0,0 +1,28 @@
+type QueryClient = {
+    query: (query: string, values: unknown[]) => Promise<{ rowCount?: number | null }>
+}
+
+type TenantImportData = {
+    tenantId: number
+    tables: Record<string, Record<string, any>[]>
+}
+
+export const restoreImportedTenantNumberRanges = async (
+    client: QueryClient,
+    exportData: TenantImportData
+) => {
+    const tenantRow = (exportData.tables.tenants || []).find(
+        (row) => Number(row.id) === Number(exportData.tenantId)
+    )
+
+    if (!tenantRow || tenantRow.numberRanges === null || typeof tenantRow.numberRanges === "undefined") {
+        return 0
+    }
+
+    const result = await client.query(
+        `update "tenants" set "numberRanges" = $1::jsonb where "id" = $2`,
+        [JSON.stringify(tenantRow.numberRanges), exportData.tenantId]
+    )
+
+    return result.rowCount || 0
+}
diff --git a/backend/tests/tenantImportNumberRanges.test.ts b/backend/tests/tenantImportNumberRanges.test.ts
new file mode 100644
index 0000000..feeff0b
--- /dev/null
+++ b/backend/tests/tenantImportNumberRanges.test.ts
@@ -0,0 +1,48 @@
+import assert from "node:assert/strict"
+import test from "node:test"
+
+import { restoreImportedTenantNumberRanges } from "../src/utils/tenantImportNumberRanges"
+
+test("restores number ranges when importing into an existing target tenant", async () => {
+    const queries: { query: string, values: unknown[] }[] = []
+    const numberRanges = {
+        invoices: { prefix: "RE-", suffix: "", nextNumber: 4712 },
+    }
+    const client = {
+        async query(query: string, values: unknown[]) {
+            queries.push({ query, values })
+            return { rowCount: 1 }
+        },
+    }
+
+    const updated = await restoreImportedTenantNumberRanges(client, {
+        tenantId: 42,
+        tables: {
+            tenants: [{ id: 42, name: "Zieltenant", numberRanges }],
+        },
+    })
+
+    assert.equal(updated, 1)
+    assert.deepEqual(queries, [{
+        query: `update "tenants" set "numberRanges" = $1::jsonb where "id" = $2`,
+        values: [JSON.stringify(numberRanges), 42],
+    }])
+})
+
+test("does not overwrite number ranges when the export contains none", async () => {
+    let queryCalled = false
+    const client = {
+        async query() {
+            queryCalled = true
+            return { rowCount: 1 }
+        },
+    }
+
+    const updated = await restoreImportedTenantNumberRanges(client, {
+        tenantId: 42,
+        tables: { tenants: [{ id: 42, name: "Zieltenant" }] },
+    })
+
+    assert.equal(updated, 0)
+    assert.equal(queryCalled, false)
+})