The aim of the study was to analyse the viability and differentiation of the degree of low temperature resistance of one-year-old Scots pine (Pinus sylvestris L.) seedlings after wintering in the field. Nursery material was grown from seeds collected from 4 seed objects growing in the following forest districts: Kędzierzyn (P1), Chrzanów (P2), Rudy Raciborskie (P3) as well as seed orchard in the Miechów Forest District (P0). In addition, a sample of seedlings showing signs of damage (P4) was also analysed (Table 1). The electrical conductivity of electrolytes released from shoots (SEL – Shoot Electrolyte Leakage) and roots (REL – Root Electrolyte Leakage) of pine seedlings were measured. The obtained results were compared with the assessment of the electrical conductivity (EC) of the shoot and root (the so-called admittance) of the same seedlings. Using the regression equations, the relationship between seedling growth parameters and SEL and REL values was estimated. Containerized pine seedlings, hibernating in external production beds, have shown a greater share of damage caused by low temperature compared to bare root seedlings, wintering in artificial substrate. Differentiation between individual provenances was demonstrated in terms of all analysed viability indices, which suggests a different degree of resistance of cell membranes to the damage caused by low temperature (Table 2). Classification of seedlings as damaged or nonviable based on a visual assessment of the occurrence of signs of damage was confirmed in 80% by measuring their viability (Fig. 1). Along with the increase in height and size of the seedling sturdiness quotient (SQ), the share of seedlings showing damage to the root system increased – showing a higher REL value (Fig. 2). Based on the research, it is recommended to test the viability of the seedlings at the end of the winter, even if no signs of damage had been observed, as the damage may have occurred at the cellular level. Assessment of the level of electrolyte leakage from root and shoot cells released as a result of frost damage is a good and quick indicator of seedling viability.