The information content of the earnings announcement is one of the dominant topics of research in the domain of finance and accounting. Many studies have been conducted on large, developed capital markets, while on small and developing markets such as Croatian, this topic has rarely been investigated. Therefore, the goal of this research was to examine the informativeness of earnings announcements (quarterly and annually) in the context of investors on the Croatian capital market. The research was carried out using the "event study" method, and the reaction of investors was monitored by calculating the volatility of abnormal return and abnormal trading volume in the period of 7 days before, on the day and 7 days after the announcement of the accounting profit. The sample included 55 companies and their 1408 announcements, more precisely 1146 quarterly and 262 annual announcements of accounting earnings in the period from 2010 to 2020. In the observed period, there was a stock price reaction to almost every announcement, while a trading volume reaction rarely appeared. As a general conclusion, it can be stated that the earnings announcement has an informational value for participants in the capital market, but that the Croatian capital market is inefficient in terms of information because it enabled investors to achieve abnormal returns. More precisely, the empirical results on the occurrence of significant abnormal return volatility indicate that the earnings announcement affects the stock price. While, the results of the abnormal trading volume indicate that investors do not differ significantly in their interpretations of the announcement. For further research, it is recommended to investigate additional factors that explain the occurrence of observed abnormal returns and the absence of significant abnormal trading volume in the event period.