Increasing the early season cold tolerance of maize (Zea mays L.) has the potential to lengthen its growing season and enhance yields. Early-planted maize is often exposed to cold nighttime temperatures and bright morning light, conditions that can damage photosynthetic tissues and delay seedling vigor. This study was undertaken to determine if there is genetic variation for the capacity of maize inbred seedlings to accumulate biomass under cold stress. Five experiments were conducted over three seasons in two locations using 21 public maize inbred lines. Cold tolerance was quantified as the ratio of dry matter accumulation per plant in early-planted plants relative to late-planted. Significant effects of genotype, planting date, environment and their interactions were detected for cold tolerance. Genotypic variation for cold tolerance was significant in four of five environments. Nine genotypes - F2, CG60, CG33, CG105, F7, CG57, CG69, MO17 and CG24 – ranked consistently as cold tolerant with high early/late planting biomass ratio, each line under cold stress retaining more than 63% of control dry weight. Three inbreds - CG76, CG108, and CG102 - were classified as cold susceptible with low dry weight ratio, each line retaining less than 44% of the control dry weight. Cold-tolerant genotypes could be used to generate cold tolerant hybrids