A toner for developing electrostatic images is prepared from a binder resin, a colorant or magnetic material, and a wax component. The toner is provided with improved low-temperature fixability anti-electrostatic offset characteristic, anti-blocking characteristic and anti-offset characteristic by controlling the thermal characteristic of the wax component so as to provide a DSC (differential scanning colorimeter) curve on temperature increase, showing a minimum onset temperature of heat absorption of at least 50.degree. C. and at least two heat absorption peaks including a largest and a second largest peaks, different from each other in peak temperature by at least 15.degree. C., wherein low-temperature heat absorption peak P.sub.1 of the two peaks shows a half-value width of at most 20.degree. C. and a higher-temperature heat absorption peak P.sub.2 shows a half-value width of at most 20.degree. C., and wherein the peak P.sub.1 shows a higher half-width temperature and the peak P.sub.2 shows a lower half-width temperature different form the higher half-width temperature of the peak P.sub.1 by at least 5.degree. C.