Empirical prediction equations of the form W = aQ(h) have been reported for rills and rivers, but not for ephemeral gullies. In this study six experimental data sets are used to establish a relationship between channel width (W, m) and flow discharge (Q, m(3) s(-1)) for ephemeral gullies formed on cropland. The resulting regression equation (W = 2.51 Q(0.412); R-2 = 0.72; n = 67) predicts observed channel width reasonably well. Owing to logistic limitations related to the respective experimental set ups, only relatively small runoff discharges (i.e. Q < 0.02 m(3) s(-1)) were covered. Using field data, where measured ephemeral gully channel width was attributed to a calculated peak runoff discharge on sealed cropland, the application field of the regression equation was extended towards larger discharges (i.e. 5 x 10(-4) m(3) s(-1) < Q < 0.1 m(3) s(-1)).