Sirtuin 1 (SIR1) is a NAD+-dependent nuclear deacetylase that is involved in various metabolic pathways affecting energy homeostasis. In this investigation,we aimed to study the association of three SIRT1 gene single nucleotide polymorphisms (SNPs); rs7895833 A/G, rs7069102 C/G and rs2273773 C/T, located on the promotor, intron and exon regions respectively, with essential hypertension and type 2 diabetes mellitus (T2DM). The three SNPs were genotyped using polymerase chain reaction with confronting two pair of primers (PCR-CTPP) method in a group of non-diabetic essential hypertensive patients, a group of patientswith essential hypertension and T2DM, in addition to a group of healthy controls. The results of the investigation revealed that G-allele of rs7895833 A/G increased in the patients compared to the controls (P = 0.046), [OR (95% CI) was 0.72 (0.5–1)] and GG genotype and G-allele frequencies of rs7069102 C/G, were significantly higher in patients compared to the controls (P=0.0045 & b0.0001, respectively). Regarding rs2273773 C/T, TT-genotype and T-allele increased significantly in the patients compared to the controls (P = 0.016 & 0.04, respectively), respectively). No significant differences in the genotypes or alleles frequencies were found between the patient groups. We conclude that genetic polymorphisms in SIRT1 gene might play a role in the pathogenesis of essential hypertension and both essential hypertension and T2DM share similar pathogenic mechanism.