ABSTRACT 

This research work was on the appraisal of internal control system as a means of preventing fraud in Nigerian Financial Institutions. 

However for a more detailed study a case study was carried on First Bank Plc Onitsha Head Office.  The bank understudy was selected by simple random sampling. 

This study was necessitated because of the Increasing wave of Bank fraud in Nigerian in recent times as reported by the Nigerian dailies.  Therefore the need to investigate these reports and if confirmed, a financial institution and to what extent the application of an effective internal control system can go to help matters. 

All aspects of this work is very relevant in one way or the other to the Nigeria Banking Industry, as a whole, and for those who may be interested in carrying out further study in this topic.

The research design is the survey approach that is the cross sectional survey type of descriptive research which requires the selection of respondents from a population.  The population of the study is made up of the Senior Officer of the Bank under study who has worked in the Bank for more than five years. 

In determining the sample size Bowleys formulars on sampling was used while the allocation of questionnaires to the bank was done randomly. 

Also data were collected through primary and secondary sources, the primary sources of data are mainly through personal interviews and distribution of questionnaires while the secondary source include Books, Journals, Newspapers and Magazines. 

The method of statically analysis includes the use tables, percentage analysis and logical deductions while the significant tests of two means was used in testing the hypothesis.

From my finding, it was ascertained that Banks have the best internal control system in Nigeria.  The internal control system is both adequate and effective, although more operative improvement and reviews is vital.  The Management of Bank should be at alert so as to close any loophole that may arise in their internal control system.  Also it was discovered that the major cause of fraud is the employment of dishonest staff.  The fore staff qualities like integrity should be ascertained before employment.  There should be an increased enlightens on the legal implications of fraud among other.