A large sample method for obtaining asymptotic simultaneous confidence bands for a three-parameter logistic response curve is described. Simultaneous confidence bands indicate the sampling variation of item response curves relative to a fitted function. A procedure is given which requires as input maximum likelihood parameter estimates and an asymptotic error covariance matrix. Illustrative plots of item response curves with corresponding confidence bands are presented. These procedures are simple enough computationally to be used economically in regular item response studies. Incorporating the calibration and graphical display of simultaneous confidence bands into calibration software would greatly benefit test designers. (Contains four figures and seven references.) (Author/SLD)