One hundred nine patients with essential hypertension were studied (50 male and 59 female, mean age - 62,6-/+1,08 years). Seventy six patients had left ventricular hypertrophy measured by echocardiography. NOS3 polymorphisms (Glu298Asp and ecNOS4a/4b) were studied by PCR. In patients without left ventricular hypertrophy (LVH) genotypes frequencies of NOS3 (Glu298Asp) were: Glu/Glu - 34.4%; Glu/Asp - 62,5%; Asp/Asp - 3,1%. In patients with LVH - Glu/Glu - 55.3%; Glu/Asp - 40.8%; Asp/Asp - 3.9%; p=0,117. Percent of Glu/Glu genotype was significantly higher in LVH group (p=0,047). Genotypes frequencies of ecNOS4a/4b were: in patients without LVH - 4b/4b - 37,5%; 4a/4b - 62,5%; 4a/4a - 0; in patients with LVH - 4b/4b - 21.1%; 4a/4b - 76.3%; 4a/4a - 2,6%;. p=0,151. Patients with 4a allele had higher Amax than 4b/4b patients (76,3+2,11 m/s and 67,9+4,72 m/s; p=0,040). Therefore, we show associations between Glu allele of NOS3 (Glu298Asp) and left ventricular hypertrophy and between 4a allele (ecNOS4a/4b) and diastolic dysfunction in patients with essential hypertension.