The increase in the older adult and oldest old population in Brazil is growing. This phenomenon may be accompanied by an increase in musculoskeletal symptoms such as low back pain. This condition is usually associated with disability.

To verify the association between pain intensity and disability in older adults with acute low back pain and assess whether these variables differ depending on the age group and marital status.

This is a cross-sectional study conducted with 532 older adults with acute low back pain episodes. Pain intensity was assessed through the Numeric Pain Scale and disability through the Late Life Function and Disability Instrument, which shows two dimensions: “frequency” and “limitation” in performing activities. The association between pain and disability was analyzed.

For the interaction effect between age groups and marital status, we found that the oldest old living with a partner performed activities of the personal domain less often compared to the oldest old living alone. The oldest old group living with a partner had a lower frequency of performing activities, but did not report feeling limited. The association of pain with disability was minimal (rho<0.20) and thus considered irrelevant.

Disability in older adults with acute low back pain was influenced by the interaction between age groups and marital status and is not associated with pain intensity.