In this study, bedclimate was investigated depending on three bedquilts used on ondol in winter. The environmental room condition and the ondol surface temperature were maintained 20±1℃, 50±3%R. H and 30±1℃, respectively. The materials of the experimental quilts were not different from each other. But the weights of cotton filler were 1.5, 3.0, and 4.5kg for the bedquilts. Two healthy young women were subjected for seven hour`s sleep with two replications for this study. The results are as follows. 1) The range of temperature under the mattress was higher(38.5-43.2C) than that of the temperature on the mattress(32.4-37.0C) or that of the temperature inside the bedquilts(30.2∼34.5C). The humidity inside the bedquilts was 40∼73%R.H. 2) The range of bedclimate which subjects feel comfortable were 33.6∼37.1℃ on the mattress, 30.2∼33. 6C, 42∼67%R.H. inside the bedquilts. At this range, the mean skin temperature of the subjects was was 34.7∼35.6 C. 3) When there was heating, the weight of mattress increased due to evaporation by heat from below, while wehght of other bedding increased. 4) The lower limbs are noted to be a good representative for the prediction of the skin temperature during sleep. 5) The thicker the bedquilt. the warmer and more humid the bedquilt, which induce frequent body movement during sleep, hence inferior comfort properties of bedquilts.