To study the influence of urbanization on the distribution of ant species, I compared the occurrence of several ant species in urban parks of different areas and ages in Tokyo and Chiba City, Japan. Analysis of the presence or absence of 42 species revealed that the probability of occurrence in a park was significantly associated with park area for 15 species (35.7%), with park age for five (11.9%), and with region for seven (16.7%). It is likely that different species respond differently to urbanization. Species sensitive to urbanization could be good bioindicators of urban environments. Furthermore, to estimate the influence of the modification of underground environments, Messor aciculatus was selected, because this species nests in an almost vertical shaft with many chambers, to a depth of up to 4 m. The probability of occurrence of the species in a park tended to be lower in reclaimed land and banked land than in other landforms. This fact suggests that M. aciculatus could be a bioindicator of underground modification.