Abstract Sweden has made a contribution to mammography screening research considerably disproportionate to its size. With 0.13% of the world’s population, Sweden contributed almost half of the randomized trial evidence on mammography screening. In addition to the fundamental efficacy of screening in preventing deaths from breast cancer, Swedish researchers have produced a considerable volume of research evaluating mammography screening in the routine healthcare services setting and illuminating issues of breast cancer progression and natural history. The basic result that screening prevents deaths from breast cancer has informed policy and led to substantial preservation of life internationally.