Substantial improvement is reported in a quality measure, large seed size, after only one generation of mass selection from a bulk ‘Chalimbana’ population of Zambian land races of the inbred species Arachis hypogaea L. There were large positive correlations between seed size as planted and the subsequent mean size harvested. Large seed also tended to produce an increased proportion of 2- rather than 3-seeded pods, further improving both crop uniformity and quality. Total yield was unaffected, or possibly even slightly enhanced, by planting larger kernels. The circumstantial advantages of mass as opposed to pedigree selection methods are discussed.