Protein content and gluten strength are among the most important factors influencing the quality of pasta. Gluten accounts for over 80% of the grain protein, and its properties depend on the composition of two prolamins, gliadins and glutenins, with the latter being the most influential in durum wheat. Glutenins are divided in high molecular weightglutenin subunits (HMW-GS) and low molecular weight-glutenin subunits (LMW-GS), being the former codified by Glu-A1 (usually inactive) and Glu-B1, and the latter by Glu-A3, Glu-B3 and Glu-B2. SDS-sedimentation test and Gluten Index were used to characterize two durum wheat populations, i.e. 100 modern cultivars and 135 Mediterranean landraces, and accessions were selected with high (strong), intermediate, and low (weak) gluten strength. On them, the allelic composition for the loci involved in glutenin synthesis was determined through PCR, and the amino acid composition was monitored using HPLC in nine occasions through the grain filling period. The results revealed a greater allelic diversity in the landraces when compared with the modern cultivars. Slight differences on the amino acid composition appeared between modern cultivars having high- and low-gluten strength, but those showing high gluten strength exhibited greater levels of alanine during the grain filling period when compared with the intermediate and weak materials.