Here we report the dielectric relaxation study of extended hydration sheathe of dilute aqueous solution of two DNA samples, extracted from salmon sperm (SS DNA) and calf thymus (CT DNA) at different concentrations in the frequency range of 0.3–2.1 THz. The frequency dependent complex dielectric response has been fitted according to a Debye relaxation model assuming three relaxation modes. The observed relaxation time constants do not deviate much from that of bulk water and do not follow any particular trend indicating to a marginal modification of the extended hydrogen bonded network of DNA.