The wide use of mobile phones is increasing low-income individuals' access to a large range of services. One of these services is mobile banking (m-banking). Today, m-banking represents a key vector of financial inclusion in many countries in Sub-Saharan Africa, especially in Senegal. Based on technology adoption theories applied to households in developing countries, this paper studies the determinants of the adoption and use of m-banking. We distinguish between possession or adoption from actual use of m-banking and examine the interdependence between these two decisions by using a Heckman sample selection model, through a sample of 1052 individuals in the suburbs of Dakar. Our main results are that the two decisions (adoption and use) are not independent from each other. Individual characteristics, such as education, possession of a bank account, and family network effects, are determinants of the adoption, and age, gender, and being a member of a tontine are determinants of the use. A major result of this study concerns women's low propensity to adopt m-banking because of their low levels of education. However, compared with men, when women adopt m-banking, they have a stronger propensity to use it.