While fluorescence polarization is a powerful tool for the measurement of ligand-receptor (e.g. antigen-antibody) interactions, its application in routine clinical chemistry and immunochemistry has been limited because collection of data was error prone, and because analysis of data previously required tedious and imprecise manual graphical methods. We present the series of linear and curvilinear regressions required to calculate parameters (p', Q', pf, Qf, Pb, Qb, Fb max, a and Ko) and their corresponding standard errors. The values of a and Ko are comparable to those obtained by the method of finding the minimal the sum of squares. A menu operated computer program that uses these regressions, simplifies the collection, analysis and presentation of fluorescence polarization data. A simple spread sheet system permits the insertion, deletion or modification of data. The results are presented in graphical and tabular form, either on a monitor, a printer or an X-Y plotter. The system has its own graphical routines.