The paper aims to examine determinants of R&D activity conducted by the non-financial Polish private limited liability and not-listed joint-stock companies, with the special focus on the academic entrepreneurship (firms whose management and/or supervisory board consists of at least one person with PhD or professor degree). The study intends to identify factors, which determine decisions made by management concerning commercialization of the results of the research and development activity, measured by the share of the capitalized expenditures on R&D in the fixed assets, based on literature review, the spatial statistics of patents and the probit panel analysis. Among factors influencing the R&D costs capitalized in the balance sheet we analyze firm size, ability to self-financing with the use of cash flow from operational activity, cash holdings, grants, availability of financing sources (bank loans, corporate bonds and share issue) and leverage. We also take into account companies’ growth opportunities and operational risk, that as we suppose, play a crucial role in the academic entrepreneurship in comparison to more stable companies’ managed by persons outside of the academia. The data used for analysis contains 23,667 non-public non-financial Polish limited liability and joint-stock companies for the period of 2003-2013 (235,046 firm-year observations). Findings of our research show that the effects of commercialization of the R&D activity’s outcomes positively depend on grants, the ability to self-financing, firm size, while are negatively influenced by growth opportunity and operational risk, especially in the case of academic entrepreneurship.