This study was carried out in individual cultures and in community cultures to investigate the effects of various diets (5 single diets: Phaeodactylum tricornutum (PHA), Isochrysis galbana (ISO), Tetraselmis suecica (TET), Marine Chlorella (MCH), condensed freshwater Chlorella (FCH), and 2 mixed diets: TET + ISO, TET + PHA) on the mass culture of cyclopoid copepod, Paracyclopina nana. In the individual cultures, fecundity of female P. nana fed the two mixed diets (TET + ISO, TET + PHA) was significantly higher than the fecundities of female P. nana fed the five single diets. The fecundity of the female P. nana fed PHA was lower than that fed TET and ISO. Also, P. nana nauplii fed TET, ISO and the two mixed diets developed to adult, however no nauplii developed into adult when fed PHA, FCH or MCH. In the community cultures, specific population growth rate of P. nana fed PHA was significantly lower than the specific population growth rate of P. nana fed TET, ISO and the two mixed diets. P. nana fed FCH and MCH showed negative growth and eventually all stages died on the 11th day. Our results suggest that the TET, ISO and TET + ISO diets could be the optimum diet for mass culture of P. nana. Our growth data suggest that P. nana has the potential for mass culture as a live feed organism for fish larvae.