diff --git a/check_mysql_slave.py b/check_mysql_slave.py
new file mode 100755
index 0000000..5f4010d
--- /dev/null
+++ b/check_mysql_slave.py
@@ -0,0 +1,117 @@
+#!/usr/bin/env python
+import argparse
+import sys
+import traceback
+
+import mysql.connector
+
+from checker import nagios, print_icinga2_check_status
+from checker.types import try_int
+
+"""
+## Usage example ##
+
+Target delay = 300 seconds
+Warning deviation = 10%
+Critical deviation = 15%
+
+This will set the warning levels to 330 and 270 seconds, if the delay is greater or less than these values it will return WARNING.
+The critical levels will be 345 and 255 seconds. 
+"""
+
+
+def main(args):
+    cursor = cnx = None
+    try:
+        cnx = mysql.connector.connect(user=args.username, password=args.password, host=args.host)
+        cursor = cnx.cursor(dictionary=True)
+        cursor.execute("SHOW SLAVE STATUS")
+        slave_status = cursor.fetchone()
+
+        if slave_status is None:
+            print("UNKNOWN - Could not retrieve slave status")
+            sys.exit(3)
+
+        slave_io_running = slave_status['Slave_IO_Running']
+        slave_sql_running = slave_status['Slave_SQL_Running']
+        replication_delay = try_int(slave_status['Seconds_Behind_Master'])
+        last_io_error = slave_status['Last_IO_Error']
+        last_sql_error = slave_status['Last_SQL_Error']
+
+        exit_code = nagios.STATE_OK
+        exit_msg = []
+
+        if slave_sql_running != 'Yes':
+            exit_code = nagios.STATE_CRIT
+            exit_msg.append('Slave SQL is not running!')
+        if slave_io_running != 'Yes':
+            exit_code = nagios.STATE_CRIT
+            exit_msg.append('Slave IO is not running!')
+        if last_sql_error:
+            exit_code = nagios.STATE_CRIT
+            exit_msg.append(f'Last SQL Error: {last_sql_error.strip(".")}.')
+        if last_io_error:
+            exit_code = nagios.STATE_CRIT
+            exit_msg.append(f'Last IO Error: {last_io_error.strip(".")}.')
+
+        if args.target_delay:
+            warn_deviation_max = args.target_delay * (1 + (args.warning_deviation / 100))
+            warn_deviation_min = args.target_delay * (1 - (args.warning_deviation / 100))
+            crit_deviation_max = args.target_delay * (1 + (args.critical_deviation / 100))
+            crit_deviation_min = args.target_delay * (1 - (args.critical_deviation / 100))
+            if replication_delay <= crit_deviation_min:
+                exit_code = nagios.STATE_CRIT
+                exit_msg.append('Replication is delayed!')
+            if replication_delay >= crit_deviation_max:
+                exit_code = nagios.STATE_CRIT
+                exit_msg.append('Replication is ahead???')
+            if replication_delay <= warn_deviation_min:
+                exit_code = nagios.STATE_WARN
+                exit_msg.append('Replication is delayed!')
+            if replication_delay >= warn_deviation_max:
+                exit_code = nagios.STATE_WARN
+                exit_msg.append('Replication is ahead???')
+
+        if exit_code == nagios.STATE_OK:
+            exit_msg.append('Slave is healthy! Slave SQL: running. Slave IO: running.')
+
+        exit_msg.append(f'Slave is {replication_delay} seconds behind master.')
+
+        perfdata = {
+            "replication_delay": {
+                "value": replication_delay,
+                "min": 0,
+                "unit": "s",
+            },
+        }
+
+        text_result = ' '.join(exit_msg)
+        print_icinga2_check_status(text_result, exit_code, perfdata)
+        sys.exit(exit_code)
+
+    except mysql.connector.Error as e:
+        print("UNKNOWN - Could not connect to database!")
+        print(e)
+        sys.exit(nagios.STATE_UNKNOWN)
+    except Exception as e:
+        print(f"UNKNOWN - {e}")
+        traceback.print_exc()
+        sys.exit(nagios.STATE_UNKNOWN)
+
+    finally:
+        if cursor:
+            cursor.close()
+        if cnx:
+            cnx.close()
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description='Check a MySQL slave.')
+    parser.add_argument('--host', required=True, help='The IP of the slave to connect to.')
+    parser.add_argument('--username', required=True, help='Username.')
+    parser.add_argument('--password', required=True, help='Password.')
+    parser.add_argument('--target-delay', default=None, type=int, help='The target delay in seconds.')
+    parser.add_argument('--warning-deviation', default=10, type=int, help='If the delay deviates more than this percentage from the target delay, return warning.')
+    parser.add_argument('--critical-deviation', default=15, type=int, help='If the delay deviates more than this percentage from the target delay, return critical.')
+    args = parser.parse_args()
+    main(args)
diff --git a/checker/result.py b/checker/result.py
index d02c724..e256e37 100644
--- a/checker/result.py
+++ b/checker/result.py
@@ -85,6 +85,7 @@ def print_icinga2_check_status(text_result: str, return_code: int, perfdata=None
                 "crit": 100,
                 "min": 0,
                 "max": 200,
+                "unit": "s",
             },
         }
         print_icinga2_check_status(sample_text_result, sample_return_code, sample_perfdata)
diff --git a/checker/types.py b/checker/types.py
index db1a067..58a3b04 100644
--- a/checker/types.py
+++ b/checker/types.py
@@ -1,14 +1,20 @@
 from typing import Union
 
 
-def try_float(value: str) -> Union[int, float, str]:
+def try_float(value: str) -> float:
     try:
         return float(value)
     except:
         pass
     try:
-        return int(value)
+        return float(int(value))
     except:
         pass
     raise ValueError(f"Could not convert {value} to float or int")
-    # return value
+
+
+def try_int(value: str) -> int:
+    try:
+        return int(value)
+    except:
+        raise ValueError(f"Could not convert {value} to float or int")
diff --git a/requirements-difficult.txt b/requirements-difficult.txt
index 839d0f3..e3c6f57 100644
--- a/requirements-difficult.txt
+++ b/requirements-difficult.txt
@@ -1 +1,2 @@
 tiktoken==0.5.2
+mysql-connector-python==8.3.0
\ No newline at end of file