Fifteen open-pollinated families of loblolly pine (Pinus taeda L.) were evaluated for variation in winter injury in a Kentucky progeny test at plantation age 1, and for variation in in vitro cold tolerance of needles at ages 7 and 8. Laboratory evaluations were performed on four sampling dates using the electrical conductivity method. Overall mean cold tolerance was 4.5° to 10.7°C less in November and March than in January, and January levels of tolerance differed by 4.0°C between consecutive years. Regional and family differences in both winter injury and cold tolerance were significant in all assessments. Families from the Mid-South Region were more tolerant than families from the North and South Carolina Piedmonts. Family means for January cold tolerance were significantly correlated with family mean winter injury measured 6 or 7 years previously. The results indicate potential for cold tolerance selection using laboratory screening techniques. Forest Sci. 31:926-932.