Orange-naped snakes (Furina ornata) are small elapids that occur in tropical to arid regions throughout northern and central Australia. We report on the first field-based study of this species, investigating body sizes, activity patterns, and habitat use in the semiarid MacDonnell Ranges bioregion of central Australia. Using systematic road-cruising, we encountered 69 live F. ornata along a 77-km sealed road-transect over a 12-month period from August 2009 to July 2010. Based on measures of snout-to-vent length (SVL), we found that female F. ornata (mean SVL = 459 ± 6.3 (s.e.) mm; n = 16) were larger than males (SVL = 372 ± 25.2 (s.e.) mm; n = 44) (t = 4.7358, P < 0.0001), and that both sexes were larger than previously reported from museum specimens. Despite the extreme weather variability experienced in arid Australia, we found that activity patterns were not significantly related to temperature, rainfall or humidity, and F. ornata was active in all but the single coldest month of the year. The habitat-use analysis found that F. ornata was more likely to be recorded in areas with greater cover of hummock grass (Triodia spp.) and less cover of rocky outcrops or boulders. Hummock grasslands in arid Australia have an abundant and diverse skink fauna, which may attract F. ornata, whose diet consists primarily of diurnal skinks.