This experiment was conducted to determine the optimum temperature and day-length condition for laboratory multiplication of Green Rice Leafhopper, Nephotettix cincticeps Uhler, and to obtain basic information for deriving temperature dependent growth rate function. The insects which were reared in $33-35^{circ}C$ have relatively short nymphal periods and high adult emergence rate compared with the insects which were reared in $27-29^{circ}C$ The adults which emerged in $35^{circ}C$ laid significantly smaller number of eggs than the adult reared in $27-29^{circ}C$ during their nymphal stage. Day length in $29^{circ}C$ did not have any influence to the nymphal growth, adult emergence rate and egg laying of the insect. The growth rate of the insect did not have linear relation with rearing temperature.