Purpose: To evaluate the axial length changes that occur in children 3 to 9 years of age who had cataract extraction with primary intraocular lens (IOL) implantation. Setting: Emory Eye Center, Emory University, and Egleston Children's Hospital, Atlanta, Georgia, USA. Methods: A review of 17 eyes in 15 children (mean age 6.4 years; range 3 to 9 years) who had primary IOL implantation was undertaken. Patients were followed for an average of 3.1 years. The initial and final axial length measurements and refractive errors were compared. Results: The overall change in mean axial length in the 17 eyes was 0.64 mm. The overall mean myopic shift was -1.01 diopters (D) (range -3.00 to +0.50 D). Eyes with traumatic cataracts experienced more axial elongation than eyes with developmental/congenital cataracts (0.97 mm versus -0.01 mm; P = .03). Ninety-four percent of patients obtained a final visual acuity of 20/40 or better. Conclusion: Eyes with traumatic cataracts experienced more axial elongation than eyes with developmental/congenital cataracts after cataract extraction and IOL implantation.