What inclusive education is, who teaching assistants and their tasks are, how they contribute to the education of children with disabilities, and whether they are useful to teachers in the teaching process are just some of the questions that this paper seeks to answer. Increasingly in Croatian primary schools we meet teaching assistants that are gradually taking place in the regular education system. However, it is necessary to work on their training and improvement as well as on developing cooperation with teachers, school staff and parents. In this paper the effectiveness of assistants in primary education was examined using a questionnaire. The research obtained teachers' opinions on the usefulness of assistants, whether they finished training and if they participate in the creation of the teaching process. The other point examined is their contribution to individualized programs and involvement with other children. This research was conducted on a sample of 25 subjects, primary education teachers in the area of Međimurje and Varaždin county. The research revealed interesting results, but after all it can be concluded that assistants are effective in their work and helpful to teachers in their work with students with disabilities. Assistants are seen to be in touch with teachers several times a day. However, most of them did not complete the nesecessary training. On one hand many are relatively young and mostly have finished four year high school education or on the other hand are highly educated. In many parts of the world the need for schools to respect the children diversity is being increasingly recognized. Teaching assistants’ introducement is one of the key steps for the successful inclusion of children with disabilities. In Croatia, teaching assistants were firstly introduced to schools more than 20 years ago. The path to teaching assistants’ introduction has certainly not been an easy one, thus it should serve as an incentive for higher motivation to constant improvement of the quality of our education.