Two conservation treatments are described, which have been employed to protect some of the remains of Luni, an ancient Roman town in Tuscany. The treatments consisted of brushing some areas of the mortar or grit pavements with two different consolidant resins. The same resins were applied in laboratory to mortar and grit samples, to check the efficacy of the treatments by structural, chemical, mineralogical, and physical tests. Both treatments proved effective in rendering the stone much more resistant to degradation. Besides, since algal growth was abundant on the columns and floors of many houses, the algae were isolated in axenic culture and identified, and an attempt was made to block their growth by spreading a plastic film on the stone surface. However algal growth continued, though much less conspicuous, also on the plastic film, probably because this species of algae, recognized as <i>Stichococcus bacillaris Naegeli</i>, has very low food requirements. -- AATA