Sorghum (Sorghum bicolor) is a C4 tropical crop species that have been converted to adapt to temperate conditions. However, most lines are susceptible to chilling stress during early season planting. To better understand how to improve tolerance to chilling stress in sorghum we have employed quantitative trait loci (QTL) mapping using 132 F6-F8 recombinant inbred lines from the cross between BTx623 and IS3620C under controlled and field chilling stress conditions. We have detected a number of QTLs that can be associated with genetic control of physiological parameters which include; seedling anthocyanin and chlorophyll contents, fluorescence yield, SPAD measurements, and 100 seed weight, and for germination/seedling vigor parameters including seedling (shoot and root) biomass, germination index and field emergence index. Results showed that QTLs for seedling biomass and anthocyanin content mapped to overlapping regions of SBI -06 (previously referred to as LgI). The correspondence of QTLs for physiological response to chilling stress and germination/vigor parameters will be discussed.