Till date the phenomenon of maternal transfer of photic information was reported to regulate the fetal/neonatal growth, however its influence on neonatal immune system is still an enigma. In the present study, we observed an increase in maternal plasma melatonin level under short day length (SOL) condition with a consequent decrease in TLC and LC in their respective neonates. However, a significant decrease in maternal plasma melatonin level was noted under constant darkness (DD) with an increase in TLC and LC of their neonates. The blastogenic response (BGR) to Con A of splenocytes exhibited a significant increase in neonates of SDL females and a significant decrease in the neonates of DD females. Hence, it appears that the increase in maternal plasma melatonin under SOL condition transmitted information to decrease the immune status. Continuous exposure of females to darkness (DD) negatively regulated the maternal pineal gland activity thereby decreasing their plasma melatonin level. This information was transmitted for elevation of immune status in neonates, so that they exhibit better growth and sexual maturation. Therefore, we may suggest that the maternal photic information transmitted either prenatally through placenta or postnatally via the milk regulate the hormonal profile of Melatonin to regulate the immune status of neonates in order to influence their growth and sexual maturation.