Experiments of transient pool boiling from a thick copper sample having a large thermal inertia have been carried out with pentane in saturated conditions. Measurements show that the temperature at boiling incipience is strongly influenced by the transient procedure. The effects of some parameters, such as a waiting period between a preliminary procedure and the heat input or an initial subcooling of the surface, have also been investigated to understand the mechanism leading to a delay in boiling incipience under transient conditions.