<jats:p> Methods are described for the production of the monamycins by <jats:italic>Streptomyces jamaicensis</jats:italic> in shake flasks and jar fermentors. The effects on the fermentation of variations in <jats:italic>p</jats:italic> H, temperature, medium composition, volume of inoculum, and strain of the organism are discussed. The methods employed for the extraction and for the microbiological assay of the antibiotics are outlined.