This final thesis is focusing on internal audit. The objective of the thesis is to show the process of internal audit in practice and to assess whether the internal audit is effective and serves its purpose. I am describing the process of internal audit on a company providing services. Particular steps of this internal audit are being described in this thesis while the final report of the internal auditor is included. The report describes failures which occurred and the procedure of their resolution. I came to the conclusion that internal audit helps the organization to reduce the failures and mistakes risen up by ignorance, lack of attention or lack of knowledge. Following the results of the thesis I would recommend the companies not doing...