Heteroptera are insects highly abundant and rich in the Atlantic Forest in Brazil. Despite their use as bioindicators and biocontrol agents, this group is not charismatic and thus is often not included in environmental assessments. Minas Gerais is a state in Southern Brazil with high level of species endemism where parks such as the Itacolomi State Park are suggested biodiversity hotspots. In this study we evaluated the composition, abundance and species richness of Heteroptera along a vegetational gradient (climax, early succession and rupestrian field). Samples were collected between December 2010 and October 2011, totalling 336 hours over 28 sampling events across all four seasons. One thousand individuals of 38 morphospecies were collected. Abundance was significantly higher in the Summer and lower in the Winter, and it was the highest in the rupestrian field. Richness and diversity also varied across seasons, but not between sites. The most abundant morphospecies was Euchilocoris sp. (22.1%), followed by Neostenotus sp. (21.4%), both in the Miridae family. Combining the high number of singletons identified in our study (8 spp.) with the accumulation curves that show new species records still being added in our last sampling season, we suggest that there are likely more species that were not collected. Despite the fact that our specimens were only identified to the genus level in most cases, this is the first study to characterize the Heteroptera fauna at Itacolomi State Park, as the park management plan did not include hemipterans.