The goal of this study was to investigate whether chilling tolerance of C-4 photosynthesis in Miscanthus can be transferred to sugarcane by hybridization. Net leaf CO2 uptake (A(sat)) and the maximum operating efficiency of photosystem II (?(PSII)) were measured in warm conditions (25 degrees C/20 degrees C), and then during and following a chilling treatment of 10 degrees C/5 degrees C for 11day in controlled environment chambers. Two of three hybrids (miscanes), US 84-1058' and US 87-1019', did not differ significantly from the chilling tolerant M. xgiganteus Illinois' (Mxg), for A(sat), and phi(PSII) measured during chilling. For Mxg grown at 10 degrees C/5 degrees C for 11days, A(sat) was 4.4mol m(-2) s(-1), while for miscane US 84-1058' and US 87-1019', A(sat) was 5.7 and 3.5mol m(-2) s(-1), respectively. Miscanes US 84-1058' and US 87-1019' and Mxg had significantly higher rates of A(sat) during chilling than three tested sugarcanes. A third miscane showed lower rates than Mxg during chilling, but recovered to higher rates than sugarcane upon return to warm conditions. Chilling tolerance of US 84-1058' was further confirmed under autumn field conditions in southern Illinois. The selected chilling tolerant miscanes have particular value for biomass feedstock and biofuel production and at the same time they can be a starting point for extending sugarcane's range to colder climates.