This study examined urban–rural differences in the association of access to healthcare with self-assessed health and quality of life (QOL) among old adults with chronic diseases (CDs) in China. The data of 5796 older adults (≥60) with self-reported CDs were collected from the Study on Global Ageing and Adult Health in China, including indicators of self-assessed health and QOL and information on access to healthcare. Associations of access to healthcare with self-assessed health and QOL at the 10th, 50th, and 90th conditional quantiles were determined after controlling individual and household factors, showing that urban patients who received healthcare within two weeks gave higher ratings on self-assessed health scores at the 10th and 50th quantiles. In rural areas, one-year and two-week access to healthcare was found to be associated with QOL scores at the 10th and 90th quantiles, respectively. Marginal effects of using needed health service decreased with a growth in QOL and self-assessed health scores in both urban and rural locations despite these effects being significant across the whole distribution. Overall, access to healthcare affects the self-assessed health and QOL of the elderly with CDs in China, especially in patients with poor health, though differently for urban and rural patients. Policy actions targeted at vulnerable and rural populations should give priority to reducing barriers to seeking health services.