Morphological variations in insects have been shown to be influenced by latitude and elevation. Here we show that these two parameters markedly influence the appearance of the corn leafhopper Dalbulus maidis (DeLong and Wolcott). Leafhopper samples were collected in maize from 27 localities in 10 Brazilian states, with latitudes from 5 to 28° S and elevations from 16 to 1,628 m. D. maidis was the only Dalbulus species found in the samples. Up to 10 males and 10 females of D. maidis from each collection site were evaluated for size, pigmentation, and body weight. Females were always bigger and heavier than the males in the same locality. For both sexes, there was a positive and significant correlation between the morphological variables measured and the latitude and elevation from where specimens were collected. Individuals from higher latitudes (southern region) were bigger, darker, and heavier than those from lower latitudes (northeastern region). There was also a tendency for an increase in body weight, head capsule width, and wing length at higher elevations.