This thesis presents findings from a study of fifteen multi-disciplinary child protection teams in New Jersey, USA. The agencies represented in the teams were the prosecutor's office, the Division of Youth and Family Services, law enforcement, hospitals and mental health organisations. The professionals who were members of the teams included caseworkers and supervisors from the Division of Youth and Family Services, assistant prosecutors, law enforcement officers and captains, mental health staff, social workers, psychologists, physicians, nurses, assistant district attornies and victim witness staff. The data was collected through questionnaires, direct observation and in-depth interviews. The thesis explores the teams' structures, processes and interactions from two perspectives, that of the observer and that of the team members. The general findings of the study are that the prosecutor's office dominates multidisciplinary teams in the fifteen counties of New Jersey that have them, although this domination is more marked in some teams than in others. The findings reveal differences among the teams on two dimensions: 'multidisciplinary sharing' and 'team members' perceptions of the teams'. When positive and negative values are attached to each of the two dimensions a matrix of four typologies is constructed, as follows: Depressed Team: negative multi-disciplinary sharing/negativep erceptions of the team. Realistic Team: positive multi-disciplinary sharing/positivep erceptions of the team. Repressed Team: negative multi-disciplinary sharing/positive perceptions of the team. Pessimistic Team: positive multi-disciplinary sharing/negativep erceptions of the team. Each of these team types is characterised by a complex combination of attributes which are not easily disentangled and isolated. Explanations for the findings are formulated as are suggestions for promoting multidisciplinary co-operation.