Suprayogi, Y., Clarke, J. M., Bueckert, R., Clarke, F. R. and Pozniak, C. J. 2011. Nitrogen remobilization and post-anthesis nitrogen uptake in relation to elevated grain protein concentration in durum wheat. Can. J. Plant Sci. 91: 273-282. Grain protein concentration is an important end-use suitability factor in durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn.] through its effect on cooking quality. Genetic differences in grain protein concentration are exploited in Canadian durum breeding programs, but the physiological basis of these differences remains unknown. Eighteen durum genotypes varying in grain protein concentration were grown at three pre-selected Saskatchewan locations that differ for soil nitrogen (N). These included check cultivars and six low- and six high-protein doubled haploid (DH) selections from the cross DT695×Strongfield (low- by high-protein). Plants were sampled at the anthesis, milk, dough and physiological maturity developmental stages, and dry matter and N concentration of plant parts were determined. The high-protein selections expressed 0.6 to 1.1 percentage units higher grain protein concentration than the low selections over the three environments (P<0.05), but yielded less grain than the low selections in two of the three environments. Remobilization of N from vegetative organs to grain varied with environment and accounted for 73 to 98% of grain N, the remainder made up from post-anthesis N uptake. The high-protein selections showed greater post-anthesis N uptake than the low selections in two of three environments (P<0.01), but lower N remobilization from vegetative organs to the grain than the low selections in the same environments (P<0.05). Subtle differences in N and dry matter partitioning accounted for the observed differences in grain protein concentration.