A rise in body temperature as a result of passive heating is a potent stimulus for prolactin secretion (Christensen et al. 1985) and selective face-cooling (FC) is known to attenuate the prolactin response to hyperthermia (Brisson et al. 1991). However, there is some debate as to the role that skin temperature may play in modulating the perceptual and hormonal responses to heat stress. The aim of the current study was to investigate the prolactin response to heat stress where skin temperature is high and core temperature is low due to effective sweating, and the effect that FC would have. Sixteen, non heat-acclimatised human volunteers (11 male, age: 29±9 years; BMI: 23±2 kg m^-2, mean±SD) underwent a passive heat exposure for 60 min in a sauna maintained at 58°C (13% relative humidity). Subjects were allocated to one of two experimental conditions and groups were matched for sex, age and body mass index; one group received face-cooling every 5 min (FC) whilst the other received none (CON). Heat loss mechanisms were effective in minimising the rise in core temperature to ~0.25°C with no difference between groups, whereas mean skin temperatures were elevated by 8-10°C for the 60 min duration (range: 38.7-40.3°C). Levels of prolactin remained stable and below 200 mU l^-1 for the FC group, whereas concentrations increased by more than 100% to ~450 mU l^-1 for the CON group (P<0.05; independent t test). The heart rate response was sensitive to heat stress with a peak increase of 24 beats min^-1 above resting levels by 60 min in both conditions; however, no differences were observed between groups. Ratings of overall discomfort and thermal comfort were significantly lower (P<0.05; one-way ANOVA) for FC, indicating an improved comfort with the thermal environment. We suggest that a significant component of the prolactin response to moderate passive heating is mediated by facial skin rather than core temperature, and selective cooling of the face is associated with improved perception of thermal comfort. These results indicate that the temperature of only a small part of the skin (~10%) can have a disproportionately large effect on the hormonal and perceptual responses to heat stress.