A method for converting single‐mode Gaussian beams into beams with uniform irradiance profiles is described. The design is based on a Fourier transform relation between the input and output beam functions. The efficacy of the solution is shown to depend on a parameter that contains the product of the widths of the input and output beams. Problems associated with errors in system alignment and scale are discussed. Numerical illustrations and experimental results are presented. © 1996 Society of Photo−Optical Instrumentation Engineers.