There is an increased interest in developing high-yielding hulless feed barley (Hordeum vulgare L.) with low fibre content for swine rations. However, little information on physiological basis to select for high-yielding hulless barley was available. Approximately 400 double haploid barley lines were derived from a Kunlun No. 1/CIMMYT No. 6 cross using the bulbosum method. Both parental lines were six-row feed barley types differing in seed type, leaf type, leaf area distribution, tillering, time to heading and maturity and grain yield. Although Kunlun No. 1 yielded abou t 66% of CIMMYT No. 6, its seed was hulless with a grain weight 21% larger than covered CIMMYT No. 6 seed. Hulless barley, with its reduced fibre content, is desirable in swine rations. Selected double haploid lines (100 covered lines in 1995 and 100 hulless lines in 1996), parental lines and an adapted check, Chapais were evaluated at Ottawa, ON, and Charlottetown, PEI. We found that grain yields were significantly correlated with leaf area index (LAI), dry matter (DM), length and width of flag leaves, and plant height. All of the highest yielding lines in both hulless and covered populations common to both sites were similar to the parent Kunlun No. 1 with broader, shorter and greener leaves than the parent, CIMMYT No. 6. The best covered lines yielded more than the check cv. Chapais and some of the hulless lines were similar to the check. This study suggests that selection of high-yielding low fibre double haploid barley lines based on physiological traits has potential to increase grain yield for feed barley. Key words: Hulless barley, physiological traits, yield, feed quality, double haploid