The species Cryptostegia madagascariensis Bojer ex Decne is a climbing plant native to the island of Madagascar, introduced to Brazil for ornamental purposes or out of botanical curiosity. This species has become an important invader in various parts of the world, forming self-regenerating populations and clumps, mainly in deforested areas, watercourse banks and temporary ponds in the Caatinga of north-eastern Brazil. This study was carried out in a greenhouse in order to assess the effects of salinity on the chemical characteristics of the soils studied and on the germination and vegetative behaviour of young Cryptostegia madagascariensis plants. Initially, the material from a Fluvial Neosol and a Vertisol was irrigated with saline water (0.3; 1.0; 2.0; 4.0 dS m-1). Then 19 kg of each soil substrate was placed in plastic pots with a capacity of 21 litres, and the treatments were arranged in randomised blocks with four replications.