Consider the importance of corporate governance that has emerged after the failure of many companies. There was great interest on the impact of corporate governance on the performance of companies, particularly in the UK and the US. In this context, this study examines the effect of corporate governance on the performance of firms in the UK by using a secondary data for 44 firms selected randomly from FTSE-350 firms listed on the London Stock Exchange for the period from 2010 to 2014 and this In order to obtain new results, as well as in order to avoid the financial crisis which emerged in the period between 2008 and 2009. This study was conducted by focusing on corporate governance factors namely: the size of the board and the frequency of the board meeting, where the data were analysed by using the SPSS software. The results that obtained by using ROE showed that, the relationship between the performance of the company and the size of the board and the frequency of meetings of the board is a positive relationship, while the findings that has been obtained by using ROA showed the opposite, where the relationship was negative.