Dung beetles are important bioindicator species in an ecosystem. The relationship between the CO₂ concentration and percentage of soil organic matter (SOM) with the diversity and abundance of Onthophagus species was investigated as a model genus in a model sampling area in an oil palm plantation in the southern part of Peninsular Malaysia. In total, 554 samples belonging to 25 species of Onthophagus were collected. No significant differences in CO₂ concentration during the day and night across the stations were found, except DCO₂S1 vs DCO₂S2 (p = 0.014, p < 0.05). Also, the diversity and abundance of species did not differ significantly (H'= 2.250 [diurnal] and H'= 1.854 [nocturnal]; p > 0.05). The dung beetle species recorded specifically during the day were O. aphodiodes, O. denticollis, O. cf. pacificus, O. dayacus, O. sp. 1, O. penicillatus, O. peninsulocupreus, and O."hairy group" (H'= 1.739), while O. babirussoides, O. phaenids, O. insicus, O. paraphamaeomorphos, O. peninsularis, and O. parachandrai (H'= 1.677) were observed at night. Furthermore, no relationship was discerned between % SOM vs diversity indices (r = 0.348), evenness (r = -0.289), and richness (r = 0.972) of dung beetles. This is the first study in Malaysia to illustrate a lack of relationship between CO₂ concentration and SOM with Onthophagus spp. The preliminary data of this research can be used for future studies on diversity and ecology of dung beetles in relation to CO₂ and SOM.