The main aim of the paper is a comparative analysis of the research results presented in four research projects on e-customer preferences in last-mile delivery conducted recently on the Polish e-commerce market as: Gemius Poland, PostNord and Łukasiewicz Research Network – Institute of Logistics and Warehousing Network, and own research financed by Polish National Science Center under the title "Sustainable last-mile logistics and e-commerce returns. Perspective of various stakeholder groups". E-customers in Poland are mainly guided by price, safety and delivery service standards; trust in the supplier is also important. Interestingly, in the context of the development of pro-ecological trends, it is still of minor importance for Polish e-customers whether the delivery is environmentally-friendly, including whether it is possible to return the goods in an "environment-friendly" manner. A comparative analysis of research projects regarding e-customer preferences allows to identify similarities and differences in the scope of research results, identify a cognitive gap, and define directions and recommendations for further e-customer market research. The results obtained may also contribute to the formulation of recommendations for e-commerce and logistics companies regarding e-customer preferences for last-mile delivery to increase customer satisfaction, improve efficiency, and create competitiveness.