A field trial is described, in which the response ofLupinus albusandL. angustifoliusto three levels of P and five of K was measured. The P level of the soil was moderate, but the K content was extremely low. Both species responded only slightly to P and K; significant differences were only obtained in stubble yield. The latter results suggest somewhat better response to both elements in Lalbusthan inL. angustifolius.It was concluded that lupins have an unusually efficient K uptake mechanism. Protein content and protein production of the tops and seed did not suggest any effect of the fertilizer treatments on the efficiency of nitrogen fixation. Findings of the P, K, Ca and Mg content of the tops of Lalbusat the late bud stage and the seed of both species are also reported.S. Afr. J. Plant Soil1986, 3: 193–197