Seed invigouration studies in onion cv. Bellary red were conducted at Deptt. of Seed Science and Technology, University of Agricultural Sciences, Raichur with an objective to identify suitable priming treatments for fresh and aged seeds. Priming treatments for fresh (S1) and aged seeds (S2) consisted of C1 – Control, C2 – Hydropriming, C3 - KH2P04 @ 10-1 M, C4 - KH2P04 @ 10-3 M, C5 - PEG @ -1.0 MPa, C6 - PEG @ -2.0 MPa, C7 - GA3 @ 100 ppm, C8 - GA3 @ 500 ppm, C9 - Ethrel @ 100 ppm, C10 - Ethrel @ 500 ppm, C11 - Thiourea @ 0.5%, C12 - Thiourea @ 1%, C13 - 8- hydroxy quinoline benzyl sulphate @ 0.25%, C14 - 8- hydroxy quinoline benzyl sulphate @ 0.5%, C15 - K2SO4 @ 10-1 M, C16 - K2SO4 @ 10-3 M, C17 - KNO3 @ 0.5%, C18 - KNO3 @ 1% at two different temperatures (T1 - 150 C and T2 - Ambient ). The fresh and aged seeds treated with GA3 @ 500ppm showed significantly the highest germination percentage (87.08). The fresh seeds when treated with GA3 @ 500ppm exhibited maximum seedling length, higher seedling vigour index (1410) followed by ethrel @ 500ppm. The vigour indices of fresh seeds were significantly higher than aged seeds. Fresh seeds primed with GA3 @ 500ppm showed higher field emergence % (76.08) and lower days to 50% germination (2.48 days). Among the interaction effect of priming treatments with fresh and aged seeds at different temperatures, seeds treated with GA3 @ 500ppm at temperature 150 C showed higher germination percentage (95.33), seedling length (18.37cm), seedling vigour index (1750), field emergence (81.33%) and lower days to 50% germination (2.2 days). A similar trend was also observed in aged seeds.