Transmission of scientific news through media channels involves three main communication members: scientists, journalists and society. If all three participants are active and interested in communication, effective process of science journalism or even interactive dialogue between communication members can be realized. Interaction peculiarities in communication between journalists and scientists, between scientists and society or between journalists and society are significant while describing consistency of scientific news in media channels or evaluating science journalism professionalism in the country. In this thesis peculiarities of scientists’ and journalists’ communication are analyzed and intercourses between other communication members are discussed. The aim of this thesis was to identify weaknesses of interaction between systems of science and journalism, to find out communication peculiarities in scientists’ and journalists’ socialization and to frame guidelines for professional science journalism in Lithuania, while evaluating Finish experiences. The title of the thesis - Science journalism: assumptions, experiences and challenges in Lithuania and Finland. The first objective of this thesis was to identify science journalism socio-communicational assumptions and to evaluate dominating popular science communication models according to the flow of scientific literature. It was found, that problems of accuracy and objectivity in science journalism were significant during all the development process of science communication. It is noticeable that insufficient accuracy and objectivity in popular science articles determine existing lack of professional science journalism. This situation leads to settlement of silence spiral effect between scientists, journalists and society. There are a few theoretical models, solving the communication gap problems. Two main and two additional popular science communication models are identified in this thesis – deficit model, context model, lay expertise model and interactive dialogue model. In the thesis attitude to science knowledge transmission of different models are discussed and use of main terms is represented in the parallel with models’ vicissitude. Scientists‘, journalists’ and other experts’ answers to study questions helped to examine peculiarities of science journalism in Lithuania – it was the second objective. Evaluation of science popularization media channels shoved that they do not have any common popular science strategy. Scientific knowledge are transmitted occasionally, they are desultory and do not create view of what is happening in global or at least in local science. So it is not surprising that the agreement between journalists and scientists about new specialized popular science publications is not reached: lack between new and old popular science journals in Lithuania is identified, but there is no actualization and evaluation of it. More over the case of Mokslo Lietuva shows, that sometimes there is no understanding, what are the main aims and functions of popular science magazines in general. Peculiarities of science journalism can be defined from the viewpoint of challenges to science and society, which were defined in the thesis. Both society‘s challenges to science – usefulness, engagement, openness and systematic transition of science news – and science‘s challenges to society – demand, understanding science value, critical evaluation and support – usually are without any respond. These factors enlarge the communication gap. Interviewers mentioned more problems, which could determine gap in communication between scientists and journalists: scientists still do not have understanding, that popular science is important activity in their work, scientists‘ motivation is not sufficient to create dialogue with journalists, science knowledge are devaluated by media channels too. The hypothesis, that in Lithuania specialized programs and special courses of science journalism are needed both to journalists and to scientists from various fields, was confirmed after analysis of demand and realization opportunities of science journalism in Lithuania, - that was the third objective. Though majority of interviewers stressed, that special courses could be enough, and opportunities of specialized programs were supported by minority, it was recognized, that both special programs and specialized science journalism courses could be the main tool to reduce communication gap between scientists and journalists and start to develop professional journalism. On the other hand it was observed, that science journalism professionalism support is bigger in Finland. Interviewers from Lithuania discussed a few opportunities of professional science communication education: popular science communication programs to journalists and scientists, media courses to scientists from different fields and special courses to journalism students. According to theoretical popular science communication models and analyzed interviews, popular science communication model of Lithuania was identified – the fourth objective. Results showed that there is no one purposeful model of science communication in Lithuania. Desultory flows of science information and a few journalists working in the field are not able to form systematic transmission of science knowledge. Trying to optimize popular science communication in Lithuania, the recommendations were given. It was suggested to improve formal and informal education from early childhood, differentiate media channels applying them to heterogeneous publics, establish associations unifying scientists and journalists, raise professional skills of journalists and scientists, form professional public relations between science organizations and public.