The main purpose of this nationwide follow-up study was to examine the development of self-reported lymphedema in the population of women with early-stage breast cancer in Denmark. In 2008 and 2012 two identical questionnaires were sent to the women aged 18-70 years treated for unilateral primary breast cancer in 2005 and 2006. 2293 women (87%) reported on lymphedema in 2008 and 2012. Overall 37% reported lymphedema in 2008 while 31% reported lymphedema in 2012 and severity of symptoms decreased. 50% of women treated with SLNB and reporting lymphedema in 2008 did not report symptoms by 2012 in contrast to 30% treated with ALND. However, 19% of women treated with ALND and not reporting lymphedema in 2008 had developed lymphedema by 2012. In conclusion lymphedema remains a frequent problem, years after treatment for breast cancer, though, number of women reporting lymphedema and overall severity of symptoms decreased.