Leaf beetles were studied in the Kovada Lake National Park (KL) and Kizildag National Park (KD) in Isparta province (Turkey) during April-October in 2009 and 2010. A total of 131 leaf beetle species were collected. In total, 88 species were detected from KL and 95 species from KD. Adult activity periods of the collected leaf beetle species were determined and their frequency and dominancy values were provided. The results showed slight differences in terms of the seasonal activity of the species in the two national parks. According to Shannon-Wiener index, the highest leaf beetle diversity among the studied months was found in early June (H': 4.23) and late May (H': 4.17). Sorensen similarity index of the species according to different seasonal periods showed three distinct seasonal periods: a) early April, b) late April to early July, c) late July to late October. Almost all leaf beetles showed a seasonal distribution, with the highest dominance during spring and early summer. The main reason for these different seasonal activities is that leaf beetle species are related to the quality and availability of host-plants.