North and South Vietnam show contrasting features in economic performance. Although the administrative capital is Hanoi in the North, Ho Chi Minh City, the center of the South, is leading the economic development of the whole nation. What is the reason behind this? What is the cause of the remarkable differences in economic growth between North and South even though both are in the same country which pursued the reform and marketization in the same manner? To answer the questions, existing literatures had solely relied on Putnam`s interpretation on italian case. According to Putnam`s proposition, the South that leads rapid economic development will show high level of general trust and weak ties. On the contrary, the North, in the situation of economic under-development, will reveal low level of general trust and family-based strong ties. To test the Putnam`s proposition on social capital, this article investigates the origins of social capital in Vietnam from the traditional society as well as articulate it modern features based on a survey conducted in Hanoi, and Ho Chi Minh City. The data in this research show several evidences that counter the Putnam`s proposition. The South, in spite of open and weak ties, shows high level of distrust. Meanwhile the North, in spite of strong ties, shows high level of general trust. This can be an evidence challenging to Putnam`s gloomy assessment of particular trust restricted to intimate relationships such as families and friends. Rather, particular trust based on intimate relationships can be a source of general trust, and therefore pave the way for economic and political development. That`s why we have to pay attention to positive roles of intimate relationships such as Guanxi in China, Yon`go in Korea, and Tinh cam in Vietnam.