Forty maize (Zea mays L.) inbreds and two hybrids were evaluated for day length reaction. Types considered to be insensitive, sensitive, and intermediate were found. Some could not be classified during the duration of the study. The extremes of insensitive to sensitive were found in each of the differentiation and maturity classes. This suggests that insensitivity can be incorporated into maize of different maturities and thus the development of genotypes with very wide adaptation is possible.