This paper relates a description of the conservation and restoration works carried out on lit stupas (dagobas) of Sri Lanka during the past two centuries. The main focus is on the, application engineering techniques while heeding archaeological requirements, in attending to these massive masonry edifices, during the latter part of the 20th century. The Post-restorational failure of the MlrlntW'tiya Stupa is taken as an example to highlight causes of failure, and how this event coupled With rtivh. ti'logical requirements led to the shift from complete restoration to conservation of other major upas such as Jethwanaramaya and Abhayagiriya, is described. Further, application of modern tinginrcring techniques used in circumventing imminent failure of earlier restored stupas such as Hrtinnharamaya is described.