diff --git a/libreplan-business/src/main/java/org/libreplan/business/expensesheet/entities/ExpenseSheet.java b/libreplan-business/src/main/java/org/libreplan/business/expensesheet/entities/ExpenseSheet.java
index 90b405d93..c0ebde4b3 100644
--- a/libreplan-business/src/main/java/org/libreplan/business/expensesheet/entities/ExpenseSheet.java
+++ b/libreplan-business/src/main/java/org/libreplan/business/expensesheet/entities/ExpenseSheet.java
@@ -244,6 +244,10 @@ public class ExpenseSheet extends IntegrationEntity implements IHumanIdentifiabl
             return true;
         }
 
+        if (expenseSheetLines.isEmpty()) {
+            return true;
+        }
+
         Resource resource = expenseSheetLines.iterator().next().getResource();
 
         for (ExpenseSheetLine line : expenseSheetLines) {