Image analysis was used to determine masticatory efficiency and performance before and after placement of immediate dentures. Sections of cored carrot were used as the test food and the particle size of chewed expectorated food was measured using image analysis. Measurements were shown to be accurate and reproducible. Masticatory function of immediate-denture patients was also compared with a similar number of dentate individuals and experienced complete-denture wearers. Dentate subjects were significantly (P less than .01) more efficient at masticating the test food than were the complete- or immediate-denture wearers. The new method of measurement removes the necessity for the unpleasant and unhygienic sieving process previously used in this type of study.