Sunflower is an adaptable species to the soil and climate conditions in Brazil and can be grown from north to south. The low productivity of sunflower in the north-east of the country may be related to the availability of water and soil fertility, among other factors. Among the macro and micronutrients essential for sunflower development, nitrogen and boron are those that most limit plant development. Sunflower presents significant reduction of growth and production when cultivated in regions with poor adequate rainfall distribution or without the use of irrigation. Por isso, este trabalho objetivou avaliar o desempenho dos cultivares de girassol, Helio 250 e Helio 251, em função de adubação com nitrogen e boro em condições de campo irrigado e na casa de vegetação. In general, the interaction of fertilization higher than 90 kg N ha-1 with 1 kg B ha-1, provided the highest growth and yield gains for sunflower crop. However, the phenological stages of sunflower reproductive development were not affected by N or B. The cv. H251 and H250 are best suited for forage production and oil production, respectively.