We tested the hypothesis that process characteristics of action strategies were related to entrepreneurial success in microbusinesses in the urban informal sector of Vietnam. The process characteristics were divided into four strategies: critical point planning, complete planning, opportunistic, and reactive. Success was defined as a combination of economic and subjective measures. A survey was done in Hue and Hanoi (Vietnam) among 102 street food vendors. With 62 vendors of this sample, we held in-depth interviews, which were used to test our hypotheses. The results showed that seventy percent of the business owners did not plan much. Opportunistic and planning strategies were most highly related to success, and a reactive strategy was related to failure. The latter replicates other studies in other developing countries.