Cerotoma arcuatus Olivier is a polyphagous pest of legumes [soybean, Glycine max (L.); dry beans, Phaseolus vulgaris (L.); and cowpeas, Vigna unguiculata (L.)], all of which are considered important protein sources for humans and domestic animals. Studies on the biology and temperature requirements of C. arcuatus were made under laboratory and field (cage) conditions. In the laboratory, insects were reared on soybean plants in incubators held at 18, 20, 22, 25, 28, 30, or 32°C, 70 ± 10% RH, and a photoperiod of 14:10 (L:D) h. A degree-days (DD) model developed based on the incubator data were validated in the field based on air and soil temperatures. The duration of the egg, larva-to-adult, and egg-to-adult period was inversely correlated with the temperature within the range of 18–32°C, with the highest viability found from 20 to 30°C. The temperature threshold for development and the thermal constant for the egg phase and the larva-to-adult periods were 13.6°C and 106.7 DD, 8.3°C and 399.4 DD, and 10.7°C and 489.0 DD, respectively. The DD model for the egg-to-adult period, calculated using constant temperatures in the laboratory, was found to be valid for populations of C. arcuatus in the field, based on the fluctuating air and soil temperatures, although air temperatures provided more precise predictions. These data provide support for the rational control of this pest through population predictions based on their temperature requirements.