Ancymidol was investigated as a medium supplement for long-term storage of potato plantlets in vitro.Different concentrations of ancymidol (0,10,15,and 20 μmol/L) were evaluated in growth media based on MS medium with 80 g/L sucrose.The cultures of three genotype Solanum chacosense (cha),CE76 and E3 were preserved under a 16 h photoperiod at (17±1)℃.The results showed that ancymidol had an active effect on culture viability to prolong preservation in vitro.Different concentrations of ancymidol had diverse growth-inhibiting effects.After conserved in ancymidol media,potato plantlets did not show evident abnormal shapes like vitrification and flaccidity in the following subculture,which are very frequently observed under mannitol stress.Genetic stability of potato plantlets conserved in ancymidol media was analyzed with randomly amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) fingerprints.Ancymidol resulted in 0.48%-2.95% genetic variations in genomic DNA of different genotypes,which will motivate us to find out better concentrations of ancymidol supplied for long-term storage of different genotypes.