Effect of conditioning of celery seeds cv.‘Makar’ and parsley seeds cv. ‘Ołomuńcka’ on dynamics of emergence and vigour of seedlings were studied in the years 2004-2005. Seeds were conditioned at temperature of 15 ºC for 7 days (only in GA3 –1 day) using the following substances: GA3 (1 g dm-3), PEG 8000 (240 g dm-3), Ekosorb Na (10 g dm-3), as well as MCE in the proportion – seeds: MCE: H2O (2:1:3). After conditioning seeds were sown to boxes filled with peat substrate. Emergence and growth of plants took place for a period of 6 weeks with light irradiation of 200 μmol m-2 s-1 and at temperatures of 24˚C during the day and 20˚C at night. The results obtained show that the substances used for conditioning parsley seeds increased the speed of emergence and the number of emerged plants by a factor of 2 to 3, while the dynamics of celery emergence and number of emerged plants were favourably influenced by PEG and GA3, but negatively by Ekosorb Na and MCE. Conditioning of seeds of both plant species resulted in an increase in the height of top parts, length of roots, fresh mass of seedlings, and contents of chlorophyll in leaves of plants. An exception were celery seedlings grown from seeds treated with MCE which, except for the length of roots, showed the lowest values of the mentioned parameters.