In order to investigate the role played by the different organs of chicken red blood cell (for example, Nucleus, Mitochondria, Microsome, etc.) in hemoglobin formation, several experiments were carried out.The results were as follows : 1) The biosyntheses of porphyrin and heme were observed in each fraction of chicken red blood cell, however, concerning the ability of biosynthesis of protoporphyrin in the supernatant fraction, a conclusion was suspended. 2) In 1000g fraction of chicken red blood cell uroporphyrin and coproporphyrin were formed at first and then protoporphyrin : in 10000g fraction uroporphyrin only was produced at first : in 20000g fraction and the supernatant fraction, the three porphyrins were simultaneously obtained from the onset.3) KCN (10-4M, 10-3M) remarkably inhibited porphyrin and hem formation in 1000g and 10000g fractions respectively, and RNA ase (0.5mg/ml) prevented porphyrin and heme formation only in 10000g fraction. Pb, (CH3COO) 2 (10-4M, 10-3M) obstructed protoporphyrin formation and incorporation of iron into heme, especially in 1000g fraction and CoCl2 (10-4M, 10-3M) inhibited porphyrin and hem formation remarkably, having no direct erythropoietic faculty. Folic acid (15mg/10ml) accelerated porphyrin formation especially in 1000g and 20000g fractions, while it inhibited heme formation conversely, VB12 (30γ/10ml) stimulated porphyrin synthesis only in 1000g fraction, having no effect on heme synthesis. ATP (10-2M), orotic acid (10-2M) thioctic acid (10-2 M), ACTH (25I.U./10ml) etc, did more harm than good.4) The X-Ray inhibited the biosynthesis of porphyrin in all the fractions, especially at above 1000γ and protoplasmas were more influenced in heme biosynthesis.