We present the calibration of a fast and non-destructive method to estimate aboveground plant biomass measuring vegetation cover. We double-sampled vegetation cover and aboveground biomass in the Patagonian steppe using 150 plots for shrubs and 50 plots for grasses. We performed simple linear regressions between vegetation cover and biomass for the dominant species and life forms (shrubs: Mulinum spinosum, Senecio filaginoides, and Adesmia campestris; grasses: Poa ligularis, Stipa speciosa, and Stipa humilis). All regressions were significant (po:01) for green and total biomass. Whereas all grass species had similar slopes, shrub slopes differed among each other with S. filaginoides and A. campestris having the steepest slopes for green and total biomass, respectively (po:05). Life-form calibrations showed steeper slopes for shrubs than for grasses (po:05). Our regressions are a basis for a non-destructive, rapid, and inexpensive way of estimating green biomass, aboveground net primary production (ANPP), and forage availability. Our life-form equations very likely could be used to estimate biomass and ANPP in other arid ecosystems dominated by tussock grasses and shrubs. ©2006 Elsevier Ltd. All rights reserved.