We tested the hypothesis that roads in arid central Australia modify roadside hydrology and nutrient patterns creating better habitat for mistletoes (Loranthaceae). In two areas of mulga woodland near Alice Springs where mulgas (Acacia aneura) are the principal mistletoe host, we compared mistletoe abundance, and host foliar water and nutrient content between roadside and interior (100 m from the road) sites. Mistletoes were significantly more abundant close to roadsides than at interior sites and mulgas had significantly higher foliar water contents at roadside compared to interior sites. Mulga foliar P and N levels were not, however, significantly different between roadside and interior sites. We conclude that roads exert a strong influence on the adjacent biota in arid central Australia primarily through facilitating water infiltration at roadside sites.