By enabling the poor to have access to financial services, microfinance has proven to be a tool having a strong potential to reduce poverty. However, international development organizations and donors consider that, in order to contribute efficiently to poverty reduction, financial intermediation by microfinance organizations has to be sustainable. In other words, the more microfinance organizations will be sustainable, the better they will fulfill their social goal. The microfinance sector of Cameroon is characterised by a number of actors ranging from the category one through category two to category three microfinance institutions. As such, our main objective in this study was to describe how a micro finance institution builds its sustainability by identifying the various practices or means put in place. To achieve this objective, we employed the qualitative research approach through the case study strategy. Based on a number of criteria, three microfinance institutions were retained with each chosen from the various categories. An interview guide was designed to this effect involving five themes on which we collected information on the field using semi structured interviews with the selected microfinance institutions. The Information collected was analysed using content (thematic) analysis. Results obtained from this analysis reveal that the putting in place of human, organizational, technological, financial and cultural means or practices significantly enable microfinance institutions to be sustainable.