TiO2-based nanocomposites were prepared to deliver oligonucleotides into cells. The nanocomposites were designed by the immobilization of polylysine-containing oligonucleotides on TiO2-nanoparticles (TiO2·PL-DNA). We showed for the first time the possibility of using the proposed nanocomposites for treatment of hypertensive disease by introducing them into hypertensive ISIAH rats developed as a model of stress-sensitive arterial hypertension. The mRNA of the gene encoding angiotensin I-converting enzyme (ACE1) involved in the synthesis of angiotensin II was chosen as a target. Administration (intraperitoneal injection and inhalation) of the nanocomposite showed a significant (by 20-30 mm Hg) decrease in systolic blood pressure when the nanocomposite contained the ACE1 gene-targeted oligonucleotide. When using the oligonucleotide with a random sequence, no effect was observed. Further development and improvement of the inhalation nanocomposite drug delivery to systemic hypertensive disease treatment promises new possibilities for clinical practice.