This paper examines the struggle against malaria undertaken by the fascist regime in the Pontine Marshes, south of Rome, and relates it to discourses of domination of nature on the one hand, and modernization and civilization through technological networks such as health and medical networks on the other. The marshes' 'first nature' is described first of all, focusing on malaria and the difficulty of making an impact on marsh biology before the fascist enterprise and before the large-scale employment of modern technology for the subjugation, channelling and development of the marshes. Secondly, the paper focuses on the organization of medical antimalaria networks in the marshes during the years immediately preceding and during the fascist period . Thirdly, the 'second nature' produced in the marshes following the land reclamation and antimalaria projects is examined, and an assessment is provide of the fascist antimalaria project in the marshes.