Models of kinetic phenomena can be written down as differential equations or their implicit or explicit integrated forms, usually with time as the independent variable. Thus we are concerned with change and rates of change of variables of interest. This review considers MLAB, MATLAB, PCNONLIN, SCIENTIST, and S-PLUS in terms of their capabilities to estimate such models. Our examination includes both features and style of the packages considered, but focuses on kinetic modeling rather than a comprehensive review of the software.