This study examined the impact of aging and age-related maculopathy (ARM) on the inactivation of phototransduction in rod photoreceptors by measuring the recovery of the a-wave using a paired flash electroretinogram technique. Measurements were made on 32 older adults in normal retinal health, 25 with early ARM, 7 with late ARM, and 20 young adults for comparison purposes. ARM presence and severity were defined by the Wisconsin Age-Related Maculopathy Grading System based on grading of fundus photographs. The inactivation of rod phototransduction exhibited an aging-related slowing. Those with early ARM did not exhibit inactivation slowing over and above what would be expected based on normal retinal aging. Persons in the late stages of ARM exhibited dramatic slowing in inactivation kinetics. © 2005 Elsevier Ltd. All rights reserved.