The sterile insect technique has in many countries become an important control tactic for integration in area-wide integrated pest management programs against fruit flies of economic importance. An important prerequisite of these programs is the availability of adequate numbers of sterile male flies that are produced in large mass-rearing facilities. This document combines an interactive spread sheet in Excel on a CD-ROM and a procedures manual to assist in technical and economic decision making with the design, costing, construction, equipping and operating of such mass-rearing facilities. The model can be used by managers as a support tool for facility design, required investments and financial planning of facilities of different sizes using different scenarios. The software was designed using the Mediterranean fruit fly (Ceratitis capitata) as a model for planning insect mass-rearing facilities, but its default settings can be easily changed to suit any other fruit fly or other pest insect. The manual includes an appendix on site selection and biological/physical factors that need to be considered when constructing a facility and another appendix on criteria that are relevant for selecting the location and establishment of mass-rearing facilities.