All higher education institutions in Finland are committed to following the guidelines of good scientific practice and procedures to handle allegations of misconduct compiled by the Finnish Advisory Board on Research Integrity. However, there is no research available in what way institutions follow these guidelines. This article analyses the current practices of defining and dealing with plagiarism in published Master's theses. The data consist of 29 written notifications of suspected plagiarism in Master's theses that were sent to the rectors of universities and decisions on these 29 cases. Inductive content analysis was used to classify the decisions according to definitions of plagiarism, processes to deal with suspicions and sanctions for plagiarism. Due to inconsistency and perplexity in some of the decisions, classifications are overlapping. The main actor in the process is the rector of the higher education institution who bases the decision on the views of preliminary enquirer. Preliminary inquiry has replaced investigation proper and this allows the procedures to remain internal and local. There is no consensus of the definition of plagiarism, and the sanctions for plagiarism vary from nothing to an attempt to revoke a Master's degree. The adherence of the higher education institutions to the national ethical guidelines is not optimal and leads to inconsistent responses to notifications of suspected plagiarism.