This thesis deals with the restoration of masonry in ruins with the aim of mapping which restorations have been carried out at Kronobergs and Bergkvara ruins in Växjö, and to explore which restoration measures that are sustainable. During the early 20th century many of the country's cultural monuments were restored including ruins. The ruins were originally buildings built with natural stone and lime mortar and were never intended to stand without a roof. When the buildings were left to decay for various reasons, they quickly became ruins. To save the ruins and make them accessible to visitors, the ruins needed to be preserved.The results have been obtained from archive studies and observations from visits in-situ. The various restoration works carried out on Kronoberg and Bergkvara ruins has been compiled. The conclusions show that in order to carry out a successful restoration, consideration must be given to the entire overall damage picture of the ruin and past and future restoration work.