The nature of multimodal distribution of fiber length, fineness and bundle strength of the fiber mixture as a result of mixing fiber assemblies differing in fiber properties and mixing ratio has been studied. The representative values of the fiber properties, such as mean fiber length, fiber length variance and short fiber content by number and by weight, respectively, micronaire and bundle strength of the fiber mixture showing multimodal distribution have been determined from those of individual fiber assembly by the mixing rule of fiber properties. The results show that the mean fiber length, fiber length variance and short fiber content, by number or by weight, of the fiber mixture showing bimodal distribution were very close to those derived from the fiber properties of the individual fiber assembly and its number proportion or weight proportion, respectively. The mean fiber fineness of the mixture was very close to the value derived from mean fiber fineness of the individual fiber assembly and its weight proportion. The mean bundle strength of the fiber mixture measured with High Volume Instrument showed higher value by 4.5% to 12.0% than weighted mean value of bundle strength calculated from the mean bundle strength of individual fiber assembly and its weight proportion.