Conservatism and value relevance are both the main subjects of researches included in accounting literatures. The recent value relevance decreases are, according to some academics, due to increased conservative accounting because conservatism prefers credit to relevance. So this research investigates the relation between conditional conservatism and value relevance of financial reporting and their trends. This study is an applied and descriptive-correlation research in terms of the aim and the nature and method of implementation, respectively. The sample consists of 930 firm-year observations for the period from 2011 to 2015. The research findings indicate that there is a significant positive relation between conditional conservatism and value relevance of financial reporting, that is, an increase in conservatism leads to improvement of information reliability and consequently, an increase in the value relevance of financial reporting. Moreover, findings show that conditional conservatism and value relevance of financial reporting have had an incremental trend in this period.