diff --git a/erpnext/hr/doctype/salary_slip/salary_slip.py b/erpnext/hr/doctype/salary_slip/salary_slip.py
index 5fbd3b1..5f195d9 100644
--- a/erpnext/hr/doctype/salary_slip/salary_slip.py
+++ b/erpnext/hr/doctype/salary_slip/salary_slip.py
@@ -14,8 +14,12 @@
 from frappe.utils.background_jobs import enqueue
 
 class SalarySlip(TransactionBase):
+	def __init__(self, *args, **kwargs):
+		super(SalarySlip, self).__init__(*args, **kwargs)
+		self.series = 'Sal Slip/{0}/.#####'.format(self.employee)
+
 	def autoname(self):
-		self.name = make_autoname('Sal Slip/' +self.employee + '/.#####')
+		self.name = make_autoname(self.series)
 
 	def validate(self):
 		self.status = self.get_status()
@@ -418,6 +422,10 @@
 		self.set_status()
 		self.update_status()
 
+	def on_trash(self):
+		from frappe.model.naming import revert_series_if_last
+		revert_series_if_last(self.series, self.name)
+
 	def email_salary_slip(self):
 		receiver = frappe.db.get_value("Employee", self.employee, "prefered_email")