To investigate the effect of stellate ganglion block (SGB) on the cardiac uptake of 123I-metaiodobenzylguanidine (MIBG), four patients without heart disease underwent SGB. Studies were done twice: once with SGB and once without SGB. Anterior planar images and myocardial SPECT images were taken at 10 minutes and 60 minutes after MIBG injection both with and without SGB. Cardiac uptake of MIBG on planar images estimated by heart/liver ratio was significantly higher with SGB at both imaging times (p < 0.01, p < 0.05) than without SGB. SGB had no effect on the local uptake of MIBG on SPECT images. In conclusion, SGB did not change the local cardiac uptake of MIBG, but it appeared to increase the global myocardial uptake of MIBG.