An accelerated storage test was carried out on freeze-dried samples of five variants of tomato mosaic virus - from leaf material, plant sap and purified preparation with and without protectant, at 28, 37 and 45 degreesC. A model for longevity prediction of lyophilized tobamoviruses was developed. The preservation of tomato mosaic virus decreased to 10% after 0.7-2.8 years in unprotected variants and after 7.5-11 years in protected samples under real storage conditions. Experimental data have confirmed the predicted values.