In this paper, we provide answers to the currently open question of workers' participation in the employer's decision-making process from the perspective of location and the role of trade unions and workers' councils in this process, covering the entire period from the Socialist Federal Republic of Yugoslavia to the Republic of Croatia. Both bodies are charged with protecting, promoting, and advocating the rights of workers, but their place, position, and manner of acting are very different from the basis of labor law. With the aim of understanding the similarities and differences of both bodies, the observation of the social phenomenon was approached from an ideological, theoretical and practical point of view and through the ontological meaning of "why something is the way it is" and the emergence of unions and workers' councils. Through a scientific and professional understanding of trade unions and workers' councils and their normative-legal regulations, their ideological and theoretical aspect of social phenomena in practice is determined. Consistent with the above, the authors answer the following question in the paper, "To what extent are unions and workers' councils complementary, and to what extent do they affect the achievement of a common goal with respect to the protection of workers' rights?". In order to answer the question, the authors have applied the method of induction and deduction in the determination of terms from the field of labor rights, especially trade union/works council law, on the basis of which they have then analyzed their similarities and differences by describing and concretizing them, and then applied the method of comparison and the normative-dogmatic method to individual institutes through the labor law regulations of the Socialist Federal Republic of Yugoslavia and the Republic of Croatia in the period from 1973. to 2019. Based on the previously drawn conclusions, in the further consideration the method of analysis and synthesis was applied to randomly selected research related to labor law institutes in the period from 1978. to 2021., namely: Berberović J. (1990); Brajić, V. (1987); Ćupurdija M., Subašić, S. (2019); Ćupurdija M., Subašić S. (2017); Ćupurdija, M. Subašić S., (2013); Ćupurdija M. (2013), Trade unions as a factor of labor law in the Republic of Croatia; Ćupurdija M. (2013) European social dialog as a prerequisite for social security, Ćupurdija M. (2009); Gotovac V., (2007); Herman V., Ćupurdija M. (2011); Herman V., Ćupurdija M., (2010); Marinković Drača D. (2004); Ravnić A., (2004); Šokčević S., (2006); Učur M., Zlatović D., Moslavac B., Malenica I., Ćupurdija M., (2021); A while ago. M. Moslavac B., (2020) and Weiss D. (1978). The thesis was confirmed that there are significant differences between the trade union and the works council in terms of organization, working methods, but also in the area of organization, participation in labor disputes and, finally, participation in collective labor disputes against employers. From the above, it is clear that there is a need for further research in the area of improvement of labor law, namely in the extension and clearer definition of the scope of each body, the protection of workers and the application of the principle of efficiency.
