MacCueSee was written to perform routine calculations on quality control concentration values from radioimmunoassay. It is written in Microsoft QuickBASIC for the Apple Macintosh computer. The program calculates within and between assay standard deviation (S.D.) and coefficient of variation from a spreadsheet file containing concentration values of controls analyzed. It also calculates the average concentration +/- 1 S.D. and contraction +/- 2 S.D. to establish between assay ranges. Its flexibility permits varying replicates between assays and automatic exclusion of missed assays. Within assay variability calculations are made for single, duplicate, and triplicate tubes. Results are displayed and can optionally be printed. In addition to radioimmunoassay, MacCueSee can be applied to a number of analytical methods in which quality control is monitored. An example of program use is included.