Career decisions alone can no longer be the focus of career guidance to be effective in the 21st century, but have to be one of the other parts of broad horizons in comprehensive approach in order to help the individuals to think strategically and holistically about work, education, leisure and other aspects of their life (Educational policy Analysis, OECD, 2002). Decision-making skills education should have in mind the personal level of personal experience, it should also create the enabling environment helping the students to match rational and emotional levels of decision-making, supporting self-confidence and exercising informational, problem-solving skills, providing the effective communication. According to P.S. Jarvis (2003), however, high quality, current, and comprehensive information is only part of helping students make sound academic and educational choices. Students need skills to use the information effectively while trying self-knowledge to exploration. They need to develop self-reliance and focus on work activities that are important to them. They need direction to learn which workplace options can provide fulfillment and satisfaction so they can seek ways to qualify for opportunities. Finally, they need adaptability, the skill of making the best of ever-present change. This point of view demands to see decision making skills in wider context of the core competences.Contemporary career theory emphasizes a sequence of learning where information is processed into knowledge and understanding. Understanding the links between the past and present help develop the skills needed to plan and create fulfilling futures (C.Maddy-Bernstein and D.E.Dare, 1997). The wide- spread statement that decision-making becomes evident for the person when it is verbally explicit and correctly defined. This definition, according to the Cognitive Information Processing theory (Peterson, Sampson, & Reardon, 1991; Peterson, Sampson, Reardon, & Lenz, 1996), J.Denham Career solutions and the career development models, reflecting a comprehensive, integrated and holistic career development process (J.Denham, 2003) is one of the decision-making stages, when a person perceives the gap between the present reality and future life career path. A person makes a decision while considering the alternatives with the purpose to accept or reject. In this way the person develop skills of argumentative reasoning helping to evaluate the alternatives. In this context there arises a problem questions: What kind of arguments is supposed to be chosen by pupils? What are the typical mistakes which could be defined as career decision-making difficulties? What are main ways of development of career decision-making skills while exercising one of the reasoning parts - argumentative practice? Hypothesis: More developed reasoning and argumentative skills are connected with the ability to make an autonomous life path decision while understanding the essence of one or the other choice.For this reason every program dealing with the development of the decision-making skills, should mind personal abilities to participate in argumentative practice presenting and clashing arguments. A teacher on his/her turn should discus his/her pupils abilities with a pupil himself/herself, create the strategy meeting the common goals and the methods helping them to be fulfilled.The main research method is statistical analysis. The basic sample consists of Lithuanian comprehensive school pupils and teachers. The research data demonstrated the existing relation between the argumentation skills and career decidedness. Results are discussed in the context of Super's (1957, 1990) theory of career development.Key words: career decision-making, career decidedness, argumentative practice, argumentative reasoning.