The aim of this work was to study the potential of using canopy reflectance indices to provide accurate and non-destructive estimates of leaf area index (LAI) and grain yield in durum wheat (Triticum turgidum L. Var. durum). Reflectance from the vegetation was measured at four growth stages, from booting to milk-grain, in twenty five genotypes under irrigated and rainfed conditions in Lleida (NE Spain). The vegetation indices SR, NDVI, SIPI and WI were calculated from durum wheat crop reflectance. LAI was measured at each sampling time, and grain yield was determined at maturity. Correlation coefficients between LAI and the spectral indices were lower under irrigated than under rainfed conditions. NDVI seemed to be the best index for the assessment of LAI, especially in the rainfed environment. Significant positive correlations of NDVI and SR with grain yield were observed when both trials were considered together. In contrast, the relationship of WI and SIPI with grain yield was negative.