diff --git a/src/lib/server/invoice.ts b/src/lib/server/invoice.ts
index ae659d6b..1181dccc 100644
--- a/src/lib/server/invoice.ts
+++ b/src/lib/server/invoice.ts
@@ -281,6 +281,24 @@ export async function createInvoice(
 	};
 }
 
+export async function getLexOfficeVoucherNumber(rechnung: Rechnung) {
+	const request = await fetch(
+		`https://api.lexoffice.io/v1/invoices/${rechnung.lex_office_id}`,
+		{
+			method: "GET",
+			headers: {
+				Accept: `application/json`,
+				Authorization: `Bearer ${LEX_OFFICE_API_KEY}`,
+				"Content-Type": "application/json",
+			},
+		}
+	);
+
+	const response = await request.json();
+
+	return response["voucherNumber"]
+}
+
 
 
 /**
diff --git a/src/pages/api/admin/ausstellen.ts b/src/pages/api/admin/ausstellen.ts
index aa77088f..b013bb27 100644
--- a/src/pages/api/admin/ausstellen.ts
+++ b/src/pages/api/admin/ausstellen.ts
@@ -20,7 +20,7 @@ import { BASE_URI } from "#lib/constants.js";
 import { getAnsichtsausweis, getDatenblatt } from "#lib/server/ausweis.js";
 import { PutObjectCommand } from "@aws-sdk/client-s3";
 import { s3Client } from "#lib/s3.js";
-import { createInvoice, getLexOfficeRechnung } from "#lib/server/invoice.js";
+import { createInvoice, getLexOfficeRechnung, getLexOfficeVoucherNumber } from "#lib/server/invoice.js";
 import { tryCatch } from "#lib/tryCatch.js";
 import SFTPClient from 'ssh2-sftp-client';
 import {
@@ -95,6 +95,7 @@ export const GET = defineApiRoute({
 			});
 		}
 
+		let voucherNumber: string = "";
 		if (!rechnung.lex_office_id) {
 			const [result, error] = await tryCatch(
 				createInvoice(ausweis, rechnung)
@@ -109,7 +110,9 @@ export const GET = defineApiRoute({
 				});
 			}
 
-			const { id, voucherNumber } = result;
+			const { id, voucherNumber: lexOfficeVoucherNumber } = result;
+
+			voucherNumber = lexOfficeVoucherNumber;
 
 			await prisma.rechnung.update({
 				where: {
@@ -119,6 +122,8 @@ export const GET = defineApiRoute({
 					lex_office_id: id,
 				},
 			});
+		} else {
+			voucherNumber = await getLexOfficeVoucherNumber(rechnung)
 		}
 
 		const pdfAusweis = await getAnsichtsausweis(
@@ -283,7 +288,7 @@ export const GET = defineApiRoute({
 	<tr><td>IBAN</td><td>:<td>\t DE81 2004 0000 0348 6008 00</td>
 	<tr><td>BIC</td><td>:</td><td>\t COBADEFFXXX</td>
 	<tr><td>Betrag</td><td>:</td><td>\t <b>${rechnung.betrag}€</b></td>
-	<tr><td>Verwendungszweck</td><td>:</td><td>\t <b>${rechnung.lex_office_id}</b></td>
+	<tr><td>Verwendungszweck</td><td>:</td><td>\t <b>${voucherNumber}</b></td>
 	</table>
 	<br>