A transient analysis on heterogeneous nucleation under pulse heating in pool boiling is developed based on changes in Gibbs free energy and availability, with temperature distributions determined from one-dimensional transient heat conduction theory. Numerical solutions are obtained for critical radius and nucleation heat fluxes under various pulse widths in different working fluids. It is found that both the critical radius and nucleation work increase with pulse width while the nucleation heat flux decreases with pulse width. To verify the proposed theory, experiments are carried out for onset of nucleation in water, alcohol and R113 under pulse heating at different pulse widths. It is found that the experimental data for nucleation heat flux at short pulse widths agree well with the proposed transient model, and those at long pulse widths approach the previous steady model. Predicted results of critical radius, nucleation heat flux and the change in availability at various pulse widths for water, alcohol and R113 are presented and compared. (C) 2012 Elsevier Ltd. All rights reserved.