1. Introduction The world around us is shrinking continually--distances and boundaries that previously held considerable separation power have been markedly eroded by developments in technology and international cooperation. This has created many new situations of intercultural contact, highlighted previously existing identity conflicts and brought to the fore a number of new ones. To tackle the resulting challenges adequately, researchers have focused considerable effort in investigating the field of acculturation and bicultural identity formation. Although various multiculturalism issues have been studied for some time already, there is yet no widespread agreement concerning the strategies used by individuals and groups in forming a bicultural identity and in combining the ethnic and national dimensions of identity (Phinney et al. 2001, Sidanius et al.). One of the central problems of multiculturalism lies in the fact that minorities tend to draw a distinction between the ethnic and the national identity, while majority groups do not, because their ethnic and national identity usually coincide. In the current study we define these component identities as follows: ethnic identity focuses on the feeling of belonging to one's group of origin, i.e. ethnic group (Phinney 1990), while national identity refers to feelings of belonging to a larger society or a state, and involves a political or a civic component (Smith 1991, Phinney et al. 2001). For members of an ethnic minority both identities--ethnic and national--are necessary for effective adaptation (Oudenhoven 2006). Such adaptation, in turn, tends to correlate with higher life satisfaction (Pavot and Diener 2008). While most immigrant groups demonstrate a relatively strong ethnic identity, the strength of their national identity as well as the strength and direction of the relationship between their ethnic and national identity is shown to be more variable and to relate to the specific acculturation context (Phinney et al. 2001). National identity is clearly the more complicated component of the two, because embracing the national identity of the host country presumes, on the one hand, that the minorities are willing to adopt it and, on the other hand, that the host majority is ready to share it. The study reported in this article investigated the relationship between ethnic identities and the Estonian national identity (1) among different ethnic groups in Estonia. The aim of the study was to identify those aspects of identity that facilitate the development of a shared national identity. In order to be acceptable to and meaningful for both the country's ethnic minorities and the majority group, these aspects must be culturally open. A national identity constructed on their basis will be referred to below as the Estonian Open Identity (EOI). The authors' general interest was to find out whether and how the ethnic and national identity of the host group (ethnic Estonians) facilitates the development of a healthy, fulfilling bicultural identity among the country's minorities. EOI should be easily combinable with different ethnic identities and thus facilitate bicultural identity development. The principal research question underlying the study was: What are or could be the dimensions of the Estonian national identity that are open enough to allow adoption to be adopted by all ethnic groups in Estonia? 1.1 Ethnic minority acculturation and bicultural identity Preserving one's ethnic identity and adopting the national majority identity of the society or state of residence can be viewed as expressions of the two main dimensions of psychological acculturation--maintenance or loss of the original culture and adoption of or separation from the new host culture. There are several models of acculturation to account for the process of cultural and psychological change that takes place in the host and home culture, or in the national and ethnic identity of minority group members (for a comprehensive overview see LaFromboise et al. …