Purpose: Researchers point out the need to move away from examining the positive trend of corporate social responsibility (Corporate Social Responsibility - CSR) towards a critical verification and redefinition of the leading CSR assumptions. One of the current and essential research issues is Corporate Social Irresponsibility (CSI). The paper aims to identify socially irresponsible actions in the economic, legal, ethical, and philanthropic areas toward stakeholders in relation to business size. Design/methodology/approach: Empirical quantitative research was conducted. The research tool was a survey questionnaire, and the research method used was CAWI. The surveyed sample included 650 randomly selected enterprises of various sizes operating in Poland. The following research questions were asked: RQ1: In what areas (economic, legal, ethical, philanthropic) do socially irresponsible actions most often occur? RQ2: In what areas (economic, legal, ethical, philanthropic) do socially irresponsible actions towards internal (RQ2a) and external (RQ2b) stakeholders most often occur? RQ3: What are the differences in identified socially irresponsible actions in areas (economic, legal, ethical, philanthropic) depending on the size of the company? RQ4: What is the relationship between the size of the surveyed organizations and the frequency of socially irresponsible actions in various areas (economic, legal, ethical, and philanthropic) in general, about internal and external stakeholders in the surveyed enterprises? Findings: The research has shown that in the studied population of enterprises, their size does not determine the occurrence of socially irresponsible economic, legal, ethical, and philanthropic activities towards their stakeholders. Research limitations/implications: The main limitations of these studies include: subjective perceptions of frequency, limited control variables, lack of prospective longitudinal studies to demonstrate changes in the prevalence of socially irresponsible actions over time. Practical implications: The results of the empirical research and its conclusions can guide managers of enterprises regarding the avoidance of socially irresponsible actions towards stakeholders. Social implications: The article addresses an important social problem of building a basis for assessing the socially irresponsible actions of companies. The research is one of the first stages in the development of the CSI assessment methodology. Originality/value: This article pretends to fill an important research gap in the topic in question. The originality of the considerations stems from the pioneering nature of research into corporate social irresponsibility from a size perspective. (original abstract)