Neurosecretory cells in the central nervous system of Lucilia illustris were traced during postembryonic development. Five type neurosecretory cells (NSC) could be distinguished in the central nervous system of the larva by paraldehyde fuchsin (PF) stain. Type I NSC are 16∼24 $mu extrm{m}$ in diameter, 10∼12 cells with medium violet, localized in pars intercerebralis. Type II NSU are 16∼20 $mu extrm{m}$, 12 cells with strong violet, and localized in pars intercerebralis. Type III NSC are 20∼26 $mu extrm{m}$, 2 cells with strong violet, and localized in ventral part of the pars intercerebralis. Type IV NSC are ca. 12 $mu extrm{m}$, 6 cells with weak violet, and localized in lateral part of the protocerebrum. Type V NSC are 12∼15 $mu extrm{m}$, 16∼20 cells with weak or medium violet, and localized laterally and ventrally in abdominal ganglia. There are no great changes in type I, II NSC during postembryonic development, but the type III NSC appears in more ventral part of pars intercerebralis than those in larva. Type IV NSC are not detected from the stage of 3-day old pupa, and type V NSC are not detected from the stage of 1-day old pupa.