After adopting K-IFRS in Korea, there are concerns about disclosure quality under K-IFRS because K-IFRS allows more discretion than K-GAAP. Therefore it would be interesting empirical question to examine how the disclosure quality under K-IFRS (Korean International Financial Reporting Standards) affects the properties of analysts' forecasts using the very first disclosure information after the adoption of K-IFRS. We measure the disclosure quality under K-IFRS as the number of disclosure items for the first quarter of 2011 under K-IFRS and analysts' forecasts property as change in forecast divergence, calculated as the ratio of forecasts dispersion before and after the first quarter of 2011. Previous literature points out that the measurement of quality of disclosure is difficult and various indexes of disclosure quality are used (Lang and Lundholm 1993; Botosan 1997;Heflin et al. 2005). We use the amount of financial disclosure for the first quarter of 2011under K-IFRS to proxy disclosure quality following Botosan (1997). The main empirical results are as follows. First the dispersion of analysts' forecasts for firms with less amount of disclosure increases after disclosure of financial accounting information than that for firms with more amount of disclosure. Second, the dispersion of analysts'forecasts increases after the announcement of financial statements when the disclosure quality of the statement of financial position is lower than that of income statement. Third, the dispersion of analysts' forecasts increases for firms with lower disclosure quality financial information than nonfinancial information. We also perform sensitivity tests to check the robustness of our results by substituting operating income forecasts as net income forecasts,and forecasts divergence as forecast accuracy and still get consistent results. These results suggests that (1) the lower disclosure quality increases uncertainty about firms' future performance among analysts, (2) the effect of disclosure under K-IFRS on analysts' behavior may differ depending on the quality of disclosure, and (3) the adoption of K-IFRS may increase the complexity of analysts' forecasting by increasing the number of disclosure items. The results of this paper contributes to the literature by providing the early empirical evidence about the effect of adoption of K-IFRS on information environment of Korean capital market.