The use of inoculants usually lies at the heart of any program of improvement in biological nitrogen fixation. However, importing inoculants into many tropical countries is restricted because of the expense and deterioration of inocula during transfer. Simple methodologies for production of quality inoculants are presented along with results obtained in Africa using a modular system designed to suit local production of inoculants. The production of high quality inoculants involves the selection and maintenance of appropriate strains, suitable carrier selection and preparation (neutrality, sterility, good physical and chemical characteristics), the use of a simple and reliable fermentor, and the ability to pack inoculum in sterile conditions. While peat continues to be the best inoculant carrier, various composts such as filtermud show promise for regions where the peat supply is inadequate. Quality control practices are necessary to ensure a production of high quality inoculants.