Primula leucophylla Pax is endemic to the Romanian Carpathians and has a very controversial taxonomical status, with no molecular research on its populations genetic structure and taxon identification. Based on morphological traits, many authors considered this entity as a new taxon as well as a subspecies of Primula elatior (L.) Hill. In the present study the isoenzyme pattern of four enzymes: esterase Est, 6-phosphogluconate dehydrogenase 6-PGDH, shikimate dehydrogenase SKDH and superoxide dismutase SOD was investigated to show whether these isozymes can be useful as discriminatory taxonomic markers between P. leucophylla and the closely related species P. elatior. No genetic intra- and inter-specific variability was detected, in spite of all the morphological variations distinguished between these two taxa. The failure in the present study to detect polymorphic loci which could be applied in a possible identification and delimitation of P. leucophylla from P. elatior, does not rule out the possibility of an existing polymorphism in other isoenzymes.