Abstract Two feeding trials were conducted to evaluate lupinseed ( Lupinus albus L.) as a replacement for soybean meal at levels of 0, 5, 10, 15, 20, and 25% of starter diets fed to 192 pigs, from 10 to 20 kg liveweight. The acid detergent fibre and neutral detergent fibre levels in the diets increased as the proportion of lupin in the diet increased. Daily gain and daily feed intake were reduced as the level of lupin in the diet increased. Slower growth rates, when lupinseed exceeded 10% of the diet, appeared to be due to a reduction in feed intake, rather than a direct effect on amino acid composition or alkaloid content of the diets since feed efficiency was not affected by the proportion of lupinseed in the diet. Lupinseed included in the diet at a low level (5–10%) appeared to have a positive effect on growth rate and feed efficiency.