BACKGROUND Synthetic bedding has been associated with increased child wheeze and also higher allergen levels in several studies. We aimed to examine whether the association between synthetic bedding and adverse respiratory outcomes was more evident among skin-prick test (SPT) positive children. METHODS A cross-sectional survey involving a population sample of 758 (81% of eligible) school children aged 8-10 years from randomly selected schools in the Australian Capital Territory in 1999. Parental questionnaires for ISAAC respiratory symptoms and child bedding were obtained. SPT results of 10 common allergens were available on 722 of the subjects (77% of those eligible). Synthetic pillow or quilt use was termed synthetic upper bedding. RESULTS Synthetic quilt use was associated with asthma (Adjusted Odds Ratio 1.67 (1.05, 2.65)), recent wheeze (AOR 1.63 (1.03, 2.59)) and allergic rhinoconjunctivitis (AOR 2.11 (1.33, 3.34)) among SPT-positive children. However, these associations were not apparent for SPT-negative children. Similarly, increasing synthetic upper bedding use was associated with more than 12 episodes of wheeze among SPT-positive children (AOR 1.69 (1.08, 2.64), P=0.02, per category) but not SPT-negative children (AOR 0.77 (0.26, 2.21), P=0.6, per category). CONCLUSIONS The apparent association between synthetic upper bedding and adverse respiratory outcomes was evident among SPT-positive but not SPT-negative children. Prospective intervention studies that aim to examine the effect of upper bedding composition on child asthma among SPT-positive children are required.