Groups within the healthcare organisations are widespread subjects of research nowadays. Nevertheless, informal groups are rarely examined in healthcare. This study is a descriptive cross-sectional study aimed to determine the formation of informal groups and its dimensions in Turkey. A survey design was adopted and sample size was 208. The questionnaire was validated using exploratory factor analysis and Cronbach’s alpha coefficient. The study unveiled that the ownership of hospitals are prominent determinants of informal groups. Demographic, social and environmentally proximity are the main factors for public employees to take part in an informal group while intellectual life and closeness are the main factors for private sector employees. The study suggests that managers should assume the most part of responsibility to determine employee’s abilities, preferences and social features to cooperate with informal groups.