It is common cause that the advent of mobile telecommunications, particularly the mobile phone, has been immensely beneficial to developing countries. Not only has it facilitated and improved communication between individuals, but also it has enabled economies to grow faster. This paper explores an additional benefit that derives from having access to a mobile phone. It examines the developmental uses of mobile phones in two East African countries: Kenya and Uganda. It focuses on the relationship between the economic upgrading and the social upgrading or downgrading that result from the developmental uses of mobile phones. It is done by means of case studies. In Kenya, the paper looks at three developmental projects making use of the M-Pesa platform, as well as two hubs in Nairobi where original ideas are incubated. In Uganda, it explores two uses of MTN’s mobile money facility and two innovative rural agricultural projects. It finds that all the cases and projects result in economic and social upgrading, although there is also some social downgrading. The study also extends and broadens the conceptualization of economic and social upgrading as formulated by Capturing the Gains thus far. Finally, the paper shows how it differs from most other studies on the developmental uses of mobile phones in Sub-Saharan Africa – by focusing on social entrepreneurship, which, unlike private entrepreneurship, seeks primarily to create social value. With one exception, all the cases studied in this paper enhance the capacity of users of mobile phones to upgrade themselves economically and socially.