Stroma-containing chloroplasts from Zea mays and Antirrhinum majus were isolated in aqueous medium. The average dry weight of chloroplasts from Zea mays is 27·10-12 g, that of Antirrhinum majus 30·10-12 g. Water freed chloroplasts consist up to 49 or 45 percent respectively of lamellar system. The lipid content of the lamellar system of Zea mays is 49 percent, that of Antirrhinum majus 45 percent. A chloroplast of Zea mays contains on the average 920·106 chlorophyll molecules, 220·106 carotenoid molecules, 2000·106 molecules of galactolipids, 190·106 molecules of sulpholipid, 260·106 phosphatide molecules and 64·106 molecules of lipophilic quinones. In addition to phosphatidylglycerol also phosphatidylinositol and phosphatidylcholine were found. It is very probable that besides vitamin K1 the homologeous compound lacking one methylgroup is present in the chloroplasts. In contrast to the literature only 62 percent of the total leaf galactolipids are found in the chloroplasts.