The study was conducted at the Mata dos Godoy State Park in Londrina, state of Paraná, Brazil. Baited pitfall traps were installed in the forest, in adjacent abandoned pasture land, and on the borders between these two environments. Every two weeks, from June 1999 to May 2000, the traps were placed for 24 hours and the material was collected every 12 hours. The 4687 specimens of Scarabaeinae collected belong to 13 genera and 27 species. The most frequent species were Onthophagus catharinensis (Paulian, 1936) (22.1%), Onthophagus hirculus (Mannerhein, 1829) (20.1%), Dichotomius mormon (Ljungh, 1799) (13.1%), Sulcophanaeus menelas (Laporte, 1840) (12.8%), and Eurystemus parallelus (Dalman, 1824) (10.6%). The other species collected amounted to less than 4.7%. The difference in numbers of specimens collected in the three environments was not significant (K(2.72) = 0.63, p = 0.729). The distribution patterns of species composition for the different environments (ANOSIM R = 0.29, p < 0.01) and activity periods (ANOSIM R = 0.18, p < 0.01) were different. Sulcophanaeus menelas, Canthidium aff. trinodosum, O. hirculus, and E. parallelus were the most abundant species, being predominantly diurnal; the first three species were more active on abandoned pasture. Most of the Dichothomius assifer (Eschscholtz, 1822) and D. mormon specimens were captured at night. The latter species was the most abundant in edges, whereas D. assifer, Scybalochantum aff. zischkai, and O. catharinensis can be considered bioindicators because they were either exclusively or highly predominant in the best preserved areas. A larger number of individuals was observed from December 1999 through March 2000, which is the time of the year when adults of Scarabaeinae normally emerge and fly, in the studied region. The highest diversity (88.89%) was observed in February.