Adoption in 2005 of IAS/IFRS by Turkish listed companies resulted in changes in classification, valuation and disclosure of financial items. This paper makes accessible to non-Turkish speakers a detailed investigation of the results from previous ratio analysis studies identified by Balsari & Varan ( Balsari & Varan, 2014 ), in addition to presenting a more extensive analysis than Cengiz ( Cengiz, 2014 ). Eight financial ratios have been analysed before and after implementation of international standards. One set of results compares the periods 2002-2003 with 2005-2006; and the other 2004 with 2005. The companies investigated are substantially the same in both analyses, but different versions of national standards are compared against international standards. Significant differences in average Book Value of Equity per Share are found after implementation of international standards for both sets of comparisons; and for one set only, at a lower confidence level, significant differences are indicated in the leverage ratio. The major contribution of the paper is the analyses of the differences during the pre and post implementation of international standards.