The results of studies investigating the effects of storage time and temperature on variations in Poisson ratio of the skin of two greenhouse tomato varieties – Admiro and Encore were presented. In the initial period of the study, Poisson ratio of the skin of tomato fruit cv. Admiro, stored at 13°C, varied between 0.7 and 0.8. After the successive 10 days of the experiment, it decreased to approximately 0.6 and was stabilized until the end of study. By contrast, the skin of tomatoes cv. Encore was characterized by lower values and lower variability of Poisson ratio in the range of 0.4 to 0.5 during storage. The examinations involving tomato fruit cv. Admiro stored at 21°C were completed after 12 days due to fruit softening and progressive difficulty with preparing analytical specimens. The value of Poisson ratio for both varieties stored at roomtemperature fluctuated throughout the experiment to approximate 0.5.