The purpose of this study was to establish the impact of single irrigation during different growth stages on the components of sunflower yield – 1000 seed weight, test weight and head diameter. The experiment was carried out during the 2006- 2010 period in the experimental field of the Agricultural University – Plovdiv, with the PR64E83 hybrid. Variants of the experiment: 1) without irrigation; 2) optimum irrigation at 75% of FC; 3) first irrigation only; 4) second irrigation only; 5) third irrigation only. The optimum irrigation regime increased the value of 1000 seed weight, test weight and head diameter. There were no significant differences in the variants with only one irrigation.