The aim of this paper is to investigate whether corporate social responsibility (CSR) is affected by firm characteristics (firm age and size) or not. The study is conducted on a firm-level data collection through a questionnaire. The paper uses factor analysis to compose the CSR variable and nonparametric methods to examine the above associations in a sample size of 822 small and medium-sized enterprises (454 firms from Czech Republic and 368 firms from Slovakia). The results revealed that the CSR is not perceived similar in both countries leading to country differences. It was found no association between CSR and firm size. Hence, size do not matter in CSR for firms operating in both countries. However, firm age matters in CSR, especially for Slovak firms. Moreover, evidence showed that the older Slovak firms are less prone towards CSR. In the Czech sample, one indicator of CSR reflected positive relationship with firm age. The current study adds to the literature by offering insights on linking firm characteristics to CSR. By studying factors which influence CSR, the paper offers the possibility to better understand entrepreneurship mindset in the context of the Central Europe.