Purpose: Current research in the area of transport decisions indicates that the key factors decisive for the mode choice are the cost and the time of transport. The complexity of behaviours and preferences of cargo shippers as well as the diversity of supply chain configurations, along with unavailability of an appropriate dataset hinder reliable forecasting the demand for transport and planning its development by means of quantitative methods. The aim of this article is to identify the factors that affect the decisions on mode choice by cargo shippers, based on data obtained by means of a qualitative method. Design/Methodology/Approach: The decision tree methodology was used in the analysis of the research study. To analyse the decision tree on the basis of C4.5. algorithm, the authors applied the J48 module of the WEKA 3.8.4. software. Findings: The research has shown that the major attributes in selecting transport modes by cargo shippers, taking into account access to three modes of transport to the seaports hinterland, are consignment size and time pressure, then owning or having access to barge terminals by cargo shippers, and the annual volume of cargoes generated by them. Practical Implications: The results of the analysis can be useful for managers of supply chain making decisions regarding the choice of transport route. Originality/Value: The developed decision tree model provides cargo shippers with a possibility of choosing three transport modes to carry cargoes to/from the seaports: road, rail, and inland shipping, which constitutes supplementation and expansion of the studies completed so far, which usually took into account only rail and road transport.