PULSESIM is a program for modeling and simulation of PULSE data based on kinetic schemes or discrete Markov models. Experimental data of ion channel function is acquired with the program PULSE and is basically analyzed with the program PULSEFIT. PULSESIM is an additional program for both, data acquisition, i.e. data generation (simulation), and analysis (modeling). In contrast to PULSEFIT, it makes use of kinetic state models and is therefore based on the interpretation of ion channel function as a stochastic process (Markov process). Markov models are valuable tools for the investigation of the structure and function of voltage-dependent ion channels. Therefore, the main purpose of PULSESIM is the mathematical description of PULSE data based on detailed kinetic schemes (Markov models) rather than more general mathematical functions as used in PULSEFIT.