English Abstract This report is a user guide for MIDAS, a collection of stand-alone programs running on MS-DOS. MIDAS is an acronym for Modelling Incidence and Delay Adjusting Simultaneously. The main program estimates the AIDS incidence from reported data, taking into account the delay in reporting. Details of the algorithm used are published (Heisterkamp et al., 1989). The program is menu driven and a graphical representation is possible on screen and plotter. A link with a popular spreadsheet program is provided. This report is a result of collaboration with the WHO Collaborating Centre in Paris, and the Center for Mathematical Methods, and was funded by the EC Concerted Action on Mathematical Modelling.