Purpose: Introduce the concept of crowdfunding, its essence and assumptions, as well as determine its role and significance in financing start-up activities in Poland. Design/methodology/approach: For the purpose of attaining the objective and demonstrating hypotheses, data and information contained in papers and reports by Polish and European institutions and organisations like European Start-up Monitor 2015, 2016, 2018, Polskie startupy 2015, 2016, 2017, 2018, 2019 (Start-up Poland Foundation) are analysed and specialist literature is reviewed. Findings: Sources of financing of start-up activities in Europe and Poland are identified. Alternative sources of financing for innovative business activities are indicated, together with the significance of crowdfunding as a source of capital for start-ups. Originality/value: The paper addresses the important issue of social financing, a present-day source of financing for innovative projects. Knowledge about the role and significance of this form of financing for development of start-ups in Poland is scant. Alternative sources of start-up financing are explored and the role of crowdfunding in this respect is indicated.