When the renal nerves are stimulated with sinusoidal stimuli over the frequency range 0.04 - 0.8 Hz, low (±< 0.4 Hz), but not high (±> 0.4 Hz), frequency oscillations appear in renal blood flow and are proposed to increase the responsiveness of the renal vasculature to stimuli. This hypothesis was tested in anesthetized rats wherein renal blood flow responses to intrarenal injection of norepinephrine and angiotensin and to reductions in renal arterial pressure were determined during both conventional rectangular pulse and sinusoidal renal nerve stimulation. Conventional rectangular pulse renal nerve stimulation decreased renal blood flow at 2 Hz but not at 0.2 Hz or 1.0 Hz. Sinusoidal renal nerve stimulation elicited low frequency oscillations (±< 0.4 Hz) in renal blood flow only when the basal carrier signal frequency produced renal vasoconstriction, i.e. at 5 Hz but not at 1 Hz. Regardless of whether renal vasoconstriction occurred, neither conventional rectangular pulse nor sinusoidal renal nerve stimulation altered the renal vasoconstrictor responses to norepinephrine and angiotensin. The renal blood flow response to reduction in renal arterial pressure was altered by both conventional rectangular pulse and sinusoidal renal nerve stimulation only when renal vasoconstriction occurred: the decrease in renal blood flow during the period of reduced renal arterial pressure was augmented and the overshoot in renal blood flow immediately following the normalization of renal arterial pressure was attenuated. Sinusoidal renal nerve stimulation using a renal vasoconstrictor carrier frequency results in a decrease in renal blood flow with superimposed low frequency oscillations. However, these low frequency renal blood flow oscillations do not alter the renal vascular responsiveness to vasoconstrictor stimuli.