Religion of Vietnam

Although most Vietnamese list themselves as having no religious affiliation, religion as defined by shared beliefs and practices, remains an integral part of Vietnamese life, dictating the social behaviors and spiritual practices of Vietnamese individuals in Vietnam and abroad. The triple religion , referring to the synthetic combination of Mahayana Buddhism, Confucianism, and Taoism remains a strong influence on the beliefs and practices of the Vietnamese even if the levels of formal membership in these religious communities may not reflect that influence.

one of the most notable and universal spiritual practices common to Vietnamese is ancestor veneration, a practice shared with Chinese and most other Asian cultures. Practically all Vietnamese, regardless of formal religious affiliation, have an altar in their home or business where prayers are offered to their ancestors. these offerings and practices are frequently done during important traditional or religious celebrations (e.g. death, birth, marriage etc.), the starting of a new business. Belief in ghosts and spirits is common ; it is commonly believed that failing to perform the proper rituals for one's ancestors will cause them become hungry ghosts.
A 2002 Pew Research Center report claimed that only 24% of the population  claimed that only 24% of the population of Vietnam view religion as "very important."      
The constitution of the Socialist Republic of Vietnam formally allows religious freedom.