Two quantitative methods of measuring intrinsic uniformity of gamma cameras have been compared. One is a modified NEMA protocol, and the other a simpler method of data acquisition and processing that can be carried out in departments with restricted data-processing facilities. Both methods show the same trend in uniformity and lead to action being taken to rectify deterioration in performance at the same time. The use of cusum plots to monitor trends in performance and set action levels is discussed and compared with a simple plot of the data as a time series.