Root-weight densities (RWD; root weight per unit volume of soil) were measured in core samples taken from nine North Island kiwifruit orchards ranging in age from 1 to 52 years. Roots were divided into fine (< 2 mm diam.), medium (2–5 mm diam.), and large (> 5 mm diam.) fractions. In young plants, weight of fine roots was concentrated around the stem and RWD decreased both with soil depth and distance from the stem. In orchards older than 10 years, RWD of the fine-root fraction decreased with soil depth alone. Fine root weights generally conform to patterns of root-length density described by Gandar & Hughes (New Zealand Journal of Experimental Agriculture 16: 35–46, 1988). Although variability between orchards is large, the dry weight of fine roots appeared to reach a plateau of about 3 t/ha after 10 years, which corresponds approximately to the time taken for fine roots to explore the available soil volume beneath each plant completely. The combined weight of medium and large roots (i.e. structural roots) increased with increasing age. These roots made up more than 90% of root weight 15–20 years after planting.