Large conductance, Ca2+-activated K+ channels (BKCa) appear to be activated by Ca2+ influx through L-Type, voltage-gated Ca2+ channels (VGCC) in arteriolar smooth muscle cells. In these same cells, Ca2+ influx through VGCC also stimulates IP3R-dependent Ca2+ waves. However, the contribution of these IP3R-dependent events to the regulation of BKCa in arterioles is not known. To test the hypothesis that VGCC-triggered, IP3R-dependent Ca2+ signals contribute to the functional activity of BKCa, we studied isolated, cannulated hamster cremasteric arterioles by pressure myography in the absence and presence of the VGCC-agonist, Bay K 8644 (BayK, 5 nM) and the IP3R antagonist 2-aminoethoxydiphenyl borate (2-APB, 100 μM). In arterioles pressurized to 20 cm H2O (to obviate pressure-dependent activation of VGCC), the BKCa blocker tetraethylammonium (TEA, 1 mM), had no significant effect on diameter (44 ± 4 vs. 42 ± 2 μm; n = 3, p > 0.05), consistent with low activity of VGCC and BKCa. Exposure to BayK (5 nM), constricted the arterioles from 44 ± 4 to 28 ± 3 μm (p < 0.05), and in the presence of BayK, TEA (1 mM) now produced robust constriction from 28 ± 3 to 18 ± 1 μm (p < 0.05). Identical results were obtained in the presence of 2-APB (100 μM): 2-APB had no effect on resting diameter (44 ± 4 vs. 43 ± 3 μm; p > 0.05) and did not affect the subsequent responses to BayK (29 ± 2 μm; p > 0.05 vs. BayK alone) and TEA (19 ± 2 μm; p > 0.05 vs. BayK + TEA alone). Efficacy of this concentration of 2-APB was verified by complete block of phenylephrine-induced constriction and abolition of Ca2+ waves in Fluo-4 loaded preparations. Before 2-APB, phenylephrine (20 nmols) constricted arterioles by 22 ± 4 μm, in the presence of 2-APB phenylephrine-induced constriction = 0.3 ± 0.2 μm (n = 3, p < 0.05). Before 2-APB, Ca2+ wave frequency = 0.21 ± 0.06 Hz, after 2-APB Ca2+ wave frequency = 0.04 ± 0.02 Hz (n = 6, p < 0.05). These data indicate that BKCa are activated by Ca2+ influx through VGCC, and that this occurs independent from IP3R-dependent Ca2+ waves.