Investigations concerning the influence of suggestion on warmth sensations are one of the favoured topics of suggestibility research. The great uncertainty concerning the perception of objective or faked warmth stimuli turned to be favourable premisses for such experiments. Methods such as the heat illusion test (Scripture, 1893; Seashore, 1895) have been used in various investigations for many years. The main purpose of such research was to investigate relationships between this kind of test and other suggestibility measures, applied dependently or independently from a hypnotic context. However, it has been found repeatedly that the readiness to respond to faked sources of warmth is heavily dependent on situational factors. The question to be examined is whether situational factors should become a matter of research themselves in order to enlarge our knowledge concerning suggestive processes. The present study investigated some of these factors, namely: type of simulated sources of warmth; affected area of skin; and set factors preceding the actual experimental trials. By far the strongest effects were found for the set factors. When the faked stimulation was embedded in procedures enhancing plausibility, the susceptibility to react was significantly greater. It was postulated that the heat illusion procedures may be useful in assessing various conditions influencing suggestibility. The results are discussed in terms of more general psychological perspectives. Copyright © 2001 British Society of Experimental and Clinical Hypnosis