The effect of Melatonin (MEL) and p-chlorophenyl-alanine (PCPA), a β-adrenergic antagonist on immune and reproductive status was studied during reproductively active phase of Indian Passeriformes Finch, Lonchura punctulata. MEL treatment to these birds showed significant increase in the immune parameters such as spleen weight, blastogenic response of splenocytes, total leukocyte count and lymphocyte count, whereas PCPA treatment showed significant decrease in all these immune parameters. On the other hand the treatment of MEL and PCPA together to the birds showed an increase in immune parameters as compared with control group of birds. Histological observations of the spleen substantiate the data of spleen weight analysis as MEL treatment to the bird increased the splenocytes density in spleen, whereas PCPA treatment to the bird showed depletion of splenocytes in spleen. The results of the present study suggest immune-stimulatory and anti-gonadal effect of the neuro-hormone MEL in this avian species.