The Langmuir monolayer technique is one of the methods used to build models of cellular membranes and enables to investigate the interactions of membrane components with other biomolecules. This method has been applied to study the effect of edelfosine - a synthetic alkyl-lysophospholipid analog - on model lipid membranes in order to get insight into its mode of action and selectivity. Edelfosine is mainly known for its anticancer properties, although it is also applied in the treatment of other diseases, like autoimmune, anti-HIV and antiparasitic. In this review we focus on its antitumor activity (although some other aspects of its therapeutic effects are also indicated) and summarize the results obtained so far with use of the monolayer technique. The application of this method evidenced for a key role of cholesterol and membrane rafts in the mechanism of anticancer activity of edelfosine. As regards the selectivity of this drug, the obtained results proved that the difference in fluidity of tumor versus normal cell membrane is important but probably not the only factor determining an easier incorporation of edelfosine into cancer cells. Further studies show that edelfosine is of strong affinity to gangliosides, which may be considered as molecules targeting edelfosine into cancer cell membrane.