The purpose of the study was to investigate how farmers in Quang Bing Province, Vietnam have been making the transition from subsistence farming to commercial agriculture. This process began in 1986 when the Vietnam economy changed from central planning to a market orientation. The research strategy was based on case study analysis of two communes in each of three agro-ecological zones, defined as coastal, plains and mountains. Within each commune there were six embedded household case studies, i.e 36 in total. Case studies were selected purposively to capture diversity of agro-ecological zones, market access and communications, wealth and income status, and ethnic communities. Households were interviewed twice; first in either late 2006 or early 2007, and again in late 2008. The study was approached using a constructivist paradigm and a lens of livelihood analysis, focusing on resources, institutions, interventions and the dynamics of change. Particular attention was given to the development of markets (inputs, outputs, land, labour and credit) and supply chain factors. Separate measures of commercialisation were constructed based on outputs and inputs, and at the level of both individual activities and the overall household. Investigations were informed by existing theory, but no hypotheses were tested. Instead, the research focused on emergent patterns and insights, and the enrichment and modification of existing theory. A review of literature indicated that the transition from subsistence farming to commercial agriculture in Vietnam was different from other countries on account of the specific combination of low technology agriculture, typical of much of developing Asia, combined with the transformation from a centrally planned economy to a market orientation as occurred in Central and Eastern European countries. At commune level, the key determinants of commercialisation were strong physical connections to markets, with good road access being paramount. Once all weather road access for motorised vehicles was available, then rapid commercialisation occurred. Supply chains typically developed faster for outputs than inputs. New technologies that increased the yield of basic food crops, and facilitated by Government and NGO programs, led to the release of land resources no longer required for meeting food security needs. Households retained their production of food crops that provided food security, and added additional cash earning activities. At the level of individual households, the commercialisation process was led by entrepreneurial families who perceived opportunities relating to profitable activities, and combined this with hard work. Often these opportunities were linked to what they had observed or learnt elsewhere. Once first movers took up a new technology, others observed and followed. There were many enabling factors, such as access to land, access to capital, and access to credit. However, none of these could be considered a determinant, in that the absence of any one factor did not by itself preclude successful commercialisation. Absence of an active male worker was a major constraint to commercialisation, as was lack of necessary crop and livestock skills. There was evidence that income disparities were increasing between the wealthy and the poor. Output commerciality across all households averaged 88 % in 2008 and was higher for wealthy households (95 %) than poor households (83 %). All households still produced their own food crops, but these crops had low market values and hence had a low impact on the output commerciality index. Output commerciality measured in percentage terms obscured that wealthy families had net incomes almost 13 times greater than poor households. A major theoretical insight was that key commercialisation factors are multiple and context dependent. Accordingly, there is a need in any investigation for a holistic approach, based on a livelihood framework that incorporates the complexities associated with the development of markets, as well as giving consideration to the range of interventions and institutional policies that impact on livelihood development.