Stability of productive traits (fruit yield, essential oil content) of varieties of cultivated medicinal plants belonging to the species of the family Apiaceae was studied(anise, coriander, dill, parsley and fennel). The trial was carried out in five locations in 2001. The estimate of stability parameters was done after the method of Eberhart and Russell (1966). As expected significant differences for the fruit yield and the essential oil content were determined among studied genotypes. Significant F-test differences were obtained for locations, while the genotype x environment interaction, as a source of variability for the identification of the growing region, had significant values of the F-test. This was a starting point for the analysis of stability parameters of these traits. The most stable genotype is the one whose value of S(2)di tends towards 0. Bearing this in mind, the most, i.e. the least stable yield was recorded in coriander; i.e. parsley, respectively. A somewhat different situation arises from the values of S(2)di in relation to the essential oil content. According to the value of this parameter; the most, i.e. the least stable essential oil content was found in fennel., i.e. parsley, respectively
