The concept of hidden curriculum has been interpreted in various perspectives and the diversity of its functions, patterns and definitions has also cried for a more consensual platform for discussion. It has been linked with values acquisition, socialization, and maintenance of class structures (Vallance, 1991, Anyon, 1981; Bowles & Gintis, 1976), the social structure of the classroom (Dreeban, 1967), the moral dimension (Kohlberg, 1970), hegemony (Apple, 1975) and the social stratification of class, race, and gender (Apple, 1982; Aronowitz & Giroux,1985; Giroux & Purpel, 1983; Oakes, 1985; Weiss, 1988). In this study, hidden curriculum is defined as 'those practices and outcomes of schooling which, while not explicit in curriculum guides or school policy, nevertheless seem to be a regular and effective part of the school experience' (Vallance, 1991, p.40). It involves the cognitive, physical and social environment of a school (Gordon, 1982). Bloom(1972) maintains that the hidden curriculum 'is in many respects likely to be more effective than the manifest curriculum' because hidden curriculum is 'so pervasive and consistent over the many yeas in which our students attend school. Its lessons are experienced daily and learned firmly...' (p.343) and also its transmission is unconscious, thus making the students less likely to resist its influence. Also the outcomes of a hidden curriculum can either be intended or unintended. This study aims to study the functions, patterns and efficacy of the hidden curriculum as perceived by the students and teachers in a primary school in Tai Po. The research was carried out mainly through a two-week attachment scheme initiated by the Hong Kong Institute of Education in which the researcher was arranged to get first hand experience of primary school teaching in the case school. Some follow-up interviews and observation were made within the month after the two-week attachment finished. The findings from the fieldwork has inevitably turned