The study was carried out at, Main Agriculture Research Station, University of Agriculture Sciences, Raichur during 2014 kharif season, to estimate genetic variability, heritability, genetic advance and phenotypic correlation in 22 onion genotypes, collected from various parts of the country. All the onion genotypes differed significantly for all the characters studied. The highest mean plant height was recorded in Bellary Red, while, the lowest mean was recorded in NHRDF Red-3 cultivar. The highest mean number of leaves per plant and number of rings per bulb were found in N-53 and Bheema Raj cultivars while the lowest were observed in Anand-2 and Arka Kalyan respectively. Bulb yield per plot exhibited the highest values of coefficient of phenotypic and genotypic variance, while number of leaves per plant and bulb diameter exhibited the lowest values in the genotypic and phenotypic coefficient of variance, respectively. The maximum estimate of heritability in broad sense (H2BS) was noticed for days to maturity followed by bulb neck thickness, while the minimum were obtained for number of leaves per plant. Bulb yield per plot gave the highest value for genetic advance over mean, whereas, number of leaves per plant gave the lowest value. The bulb length exhibited highest positive significant association with bulb yield per plot at both genotypic and phenotypic level, followed by plant height, number of leaves per plant and bulb diameter. Thus the selection based on these characters will bring about improvement in yield.