The qualitative morphologic study of the effects of organophosphate agents on development of neural cells in culture is a promising approach as a primitive step for further physiologic, electro physiologic and molecular investigation. Parathion is an OP (Organophosphate) used as an agricultural insecticide. Improper handling of this agent causes poisoning characterized by convulsive seizures, which may sometimes lead to death. Since Parathion has been observed to be responsible for more cases of poisoning than any other OP insecticide, it is vitally important to investigate other mechanisms, besides cholinesterase inhibition, which can contribute to the neurotoxicity of paraoxon. In present study, hippocampus cells taken from rat’s neonate were introduced into the neurobasal medium supplemented with B27 serum, which is an optimum medium for the growth of the hippocampus neurons, mainly due to its ability to prevent other neuroglial cell growth. Six hippocampi were dissected out of three rat brains. Cells were mechanically isolated by triturating in a dissociation buffer. After dilution and centrifugation, cells were plated on polylysine-coated pellets containing B27/neurobasal medium. Control pellets contained only neurons, while the research samples experimental contained 10, 30, 50, 100 & 150 ?m of paraoxon. The neuronal growth was morphologically followed from early hours of culturing up to one month after. Shape of the soma and arborizations were two main qualitative criteria of observation. Our results revealed that there was no clear morphologic difference between neurons in the control group and those exposed to 10?m paraoxon. In contrast, deformity of the soma and a decrease in the number of arborization were noticed in groups exposed to 100 & 150?m and changes were prominent with increasing paraoxon concentration. The present data requires a further quantification of our study by concentrating on doses between 30 ?m to 150 ?m.