The SIRA Project, which developed a small portable dosimeter for determining personal exposures to ultraviolet radiation, is summarized. The dosimeter was intended to measure the actual exposure of humans to ultraviolet-B, and possibly ultraviolet-A, radiation, and was to be used in connection with epidemiological studies conducted by the National Cancer Institute (NCI). The dosimeter was to be an alternative to the large spectrophotometers used in laboratories and the Robertson/Berger meter that is currently used in the field. The dosimeter was used in studies conducted in San Antonio, Texas. Problems were experienced with calibrating the instrument. The calibration curves were satisfactory at low exposures and at high exposures for integrated doses; however, at intermediate exposures the scatter was too large to be useable. The dosimeters used in the NCI studies were found to be capable of providing qualitative, but not quantitative, data. The dosimeter could provide information on the differences among various exposures, either with regard to locations or individuals. The author concludes that at the present time, it has not proven possible to develop personal dosimeters that are practical and useful.