Background：Recently, concerns regarding protection provided by sunscreens in the UVA spectrum have been raised. But there is no standard testing protocol for quantifying this protection. Objective：As an ideal test methodology, the PFA test using the concept of minimal pigment darkening dose(MPPD) was evaluated to determine its ability to quantify the UVA protection provided by a sunscreen. Methods：Sunscreen products were tested on unsensitized women subjects with both UVA from a Sellas UVA lamp in a protocol similar to the sun protection factor test(SPF) and UVB by the SPF protocol. Results：The protection factors in UVA ranged from 5.0 to 5.3 depending on the type of absorber and the UVB blocking filter. Conclusion：This test method provides a realistic in vivo estimate of the amount of UVA protection provided by sunscreens. (Korean J Dermatol 2000;38(6)：735~741)