The master's thesis deals with the topic of expert evidence in the proceedings for deciding on the care and upbringing, maintenance of a child and contacts with parents. In the introduction, the reader is informed about the acute problem of excessive duration of such proceedings in Slovenia, the legislator's response to it and my hypothesis that all the participants of such proceedings could help accelerate them. In the main part of the thesis, the reader is firstly acquainted with the Slovenian legislation in force that represents the legal basis for the proceedings for deciding on the care and upbringing, maintenance of a child and contacts with parents. Then follows the chapter on court experts and the selected provisions from Court Experts, Certified Appraisers and Court Interpreters Act, with the adoption of which the legislator tried, among other things, to address the problem of too lengthy proceedings with court experts. The chapter ends with a brief presentation of evidence-taking in non-contentious proceedings, which is also the basis of evidence-taking involving a court expert. This is followed by a short description of common areas of expertise needed in proceedings for deciding on the care and upbringing, maintenance of a child and contacts with parents. The most important part of the thesis is the case-law study. It highlights dilemmas that often arise in relation to expert evidence in such proceedings. It focuses primarily on revealing the causes of excessive duration of such proceedings and provides commentaries on what could be improved to accelerate aforementioned proceedings. The purpose of this case-law study is to inform the reader that the proceedings can be sped up if only the judge, court expert, the social centre service, the participants or their attorney act in such a way that the primary goal of aforementioned proceedings – protecting the rights and legal interests of a child – is achieved within a reasonable time.