1.1. An improved mass culture method has been developed for the large, free-living amebae and tested on 4 strains of Amoeba proteus, 1 strain each of A. dubia and A. discoides, and 2 strains of Chaos chaos.2.2. Tetrahymena are added to cultures at each feeding in numbers proportional to the number of amebae present. Feeding schedules and resulting growth rates are presented.3.3. The average volume and dry mass per cell are presented for each strain of ameba. These measurements were used to compare different strains and to check variation within strains from week to week during culturing.4.4. This culture method removes the element of judgement from feeding, greatly decreases any chance of feeding errors and allows sustained production of large populations of even fragile amebae, such as A. dubia.