Pore formation in cast iron castings is driven both by shrinkage and dissolved gases, where the latter stems from supersaturated gaseous species, such as nitrogen. During solidification, nitrogen partitions between the austenite and the liquid according to the ratio between its solubility in each phase, which increases with decreasing temperature. This ratio is known as the partition coefficient. In the austenite, nitrogen mobility is very limited, which can create concentration gradients. Characterization of the partition coefficient is important because accumulation in the liquid phase facilitates reaching critical supersaturation for pore formation. However, there is conflicting information in CALPHAD databases and literature regarding its partitioning behavior. In this work, the partition of nitrogen between the primary austenite and the liquid has been assessed in a hypoeutectic cast iron alloy. To assess this issue, a sample was produced and remelted under an inert atmosphere, where austenite and the liquid established a solute equilibrium. After six days of holding, the sample was quenched and discs were extracted from the austenitic and liquid part, now martensite and ledeburite respectively. The nitrogen concentration was measured by inert gas fusion and the results point towards nitrogen accumulation in the liquid during solidification. The results indicate that there are opportunities to further explore the nitrogen partitioning in other compositions and stress the need to select the databases that more accurately portray the phenomena of interest.  Moreover, a better understanding of nitrogen partitioning can enhance the control of porosity in the processing of cast iron.