With regard to the trend of plant germplasm degradation in our country, as one of the richest countries on plant genetic resources, it is necessary to act fundamentally on conservation and maintenance of available genetic diversity. Using seed cryopreservation, as one of the Ex situ plant germplasm conservation method we can store seed for long-term, with much lower costs and without losing seed viability. In this study the effect of cryopreservation on germination and growth indices (germination percent, germination rate, seed vigour index, plantlet length, plantlet fresh weight) on orthodox seeds of seven plant species (Artemisia khorassanica, Hypericum perforatum, Origanum spp, Trigonella monantha, Phytolacca americana, Hypericum androsaemum, Datura innoxia) in two storage conditions of freezer (-20oC) and cryopreservation (-196oC) were evaluated for two months. Comparing cryopreservation and freezer treatments on each species based on t- student method, no significant differences were observed on germination and growth indices except for germination percent and germination rate. Cryopreservation may be recommended as a suitable and alternative method for healthy long term storage of orthodox seeds in germplasm resources conservation centers.