If you were hired as a manager of any department your qualified to, and that department is messy and corrupted, what would you do first to take to the successful level?

There are several wonderful answers herein already from great professionals, nothing to add

Thanks

First of all , i should looking for the team of this department, rearange and restructure it , since team is the base of everything in department and-or organization. and more it is the core of the business when you guarantee the team everything will be fixed by their hands and mine ...

Regards

1. - To refer to the internal rules of the company
2. - Take good knowledge of the department of operation and organization
3. - Analyze the causes of the disorder
4. - Analyze the attempts to corruption
5. - Try to find the right solutions
6. - Establish a discipline
7. - Intensify communication flows
8. - Reorganize the department by permutations
9. - Combating corruption, blocking the way to corrupt
10. - Eliminate all forms of attempts
11. - Disconnect all sources of corruption
12. - Permanent control
13. - Unannounced controls
14. - Introduce repressive measures
15. - Severely punish those causing disorder
16. - Severely punish persons committing the offense of corruption

Will wait for a while for a clarity in the trouble water. Identify and form a bright team and nurture them towards to the curing the troubled water. Then fish out the rotten eggs and the fishes. 

Thanks for the invite ............................ agreed with the answers Mr. Najib

I agree with Mr . omer answer. Thanks for the invitation

My first step would be to re-iterate the ethics code of the company and organize an internal/external seminar on the topic and the consequences of failure to adhere to it for the entire team. Following which the team and their performance will be closely monitored under the code of conduct. Along with it I will reorganize the department work process with the my approval being made mandatory for critical issues. If nothing seems to work then restructuring the department will be the last resort.

These kind of issues are on those areas where staff satisfaction rate is very low, first rule out why staff is unsatisfied , then work on it , automatically things will going in better way soon.