An electrophotographic toner including a blend of toner particles, and external additive particles, is provided with characteristic particle size distribution conditions, i.e., (i) a particle size distribution based on a Coulter counter measurement, including a weight-average particle size D4 of X .mu.m and Y % by number of particles having sizes of 2.00-3.17 .mu.m satisfying:-5X+35.ltoreq.Y.ltoreq.-25X+180 (1)3.5.ltoreq.X.ltoreq.6.5 (2), and(ii) a particle size distribution based on a flow particle image analyzer measurement, including A % by number of particles having circle-equivalent diameters of at least 1.00 .mu.m and below 1.03 .mu.m and B % by number of particles having circle-equivalent diameters of at least 2.00 .mu.m and below 2.06 .mu.m satisfying:B-A.ltoreq.0.30 (3).As a result, the toner is provided with a stable developing performance even in a long period of continuous image formation in a high temperature/high humidity environment.