A prototype UVA dosimeter that is responsive to the UVA wavelengths only has been developed for measurement of personal exposures. The chemical phenothiazine, cast in thin film form and which is responsive to both the UVA (320-400 nm) and UVB (280-320 nm) part of the spectrum was used and filtered with mylar. This combined system responded to the UVA wavelengths only and underwent a change in optical absorbance as a result of UVA exposure. The wavelength of 370 nm was employed for quantifying the change in optical absorbance of the combined mylar/phenothiazine dosimeter and a calibration curve determined for measuring the UVA exposures. UVA exposures to approximately 50 J cm-2 may be measured prior to saturation of the response.