Yield Version 1.0 is a program for calculating fishery yields and stock biomasses, on an absolute or per-recruit basis, and for calculating biological reference points associated with these. On starting the program, users are asked to enter values of biological parameters (e.g. growth, mortality, age at maturity and stock-recruitment relationship) and fishery parameters (e.g. length at first capture, fishing season). For each parameter, either a single value can be entered, or a probability distribution can be specified to allow for uncertainty. When calculating yields and yields per recruit, the program takes explicit account of specified parameter uncertainties, presenting results in terms of histograms. Transient projection and reference point calculations can also be made, once the extent of stochastic recruitment variability has been specified. As with CEDA and LFDA, the package includes a comprehensive context-sensitive Help system and a detailed example analysis. The download file also includes the graphics server programme required to plot the data.