This study was conducted to investigate physiological response of maize to high temperature stress. Field trial was carried out in a randomized block design with three replications during the second crop season of the year 2008 in Sanliurfa, Turkey. RI, chlorophyll content, and Chla/b were measured in laboratory. LT, DF, and GY were measured in field trial. The relations among the investigated characteristics were evaluated by correlation analysis. We found that early mature varieties had higher values with regard to chlorophyll content and GY compared to late mature varieties. However, early mature varieties had lower values with regard to RI, LT, and DF than late mature varieties. Correlation analysis revealed significant relations among the characteristics measured. It was concluded that early mature varieties having lower LT and RI levels compared to late mature varieties might be recommended as second crop for the region with extremely high temperatures during the second crop season.