The random amplified polymorphic DNA (RAPD) technique was used to characterize 18 reference strains of microalgae, mostly Chlorella species, collected from various localities around Korea peninsular. Eighteen strains consist of four genera of the family marine Chlorella from 12 samples, two genera of fresh water Chlorella from three samples, and three genera on Nannochloris. Twenty 10-mer anonymous primers were screened for amplification of genomic DNA extracted from samples using the CTAB extraction method. Nineteen of these oligonucleotide primers were positive or band producing. Three of 20 random primers (OPA 10, OPA 12, and OPA 18) resulted in both clear band and a high degree of reproducibility and showed some potential to be used to discriminate individual samples of both genetically hetero-and homogeneous populations, in determining phylogenetic relationships between species within a genus and developing individual fingerprints for each samples.