Factors contributing to gait difficulties in elderly persons are considered to be multifactorial and are not well understood. The purpose of this study was to examine the association of blood pressure (BP) with change in lower limb function in older persons. Eight hundred eighty-eight older Catholic clergy members without baseline dementia or Parkinson's disease were recruited from about 40 groups across the United States. At baseline, BP was measured, the presence of vascular diseases and diabetes was recorded, cognitive function was assessed, and medications were inspected. At baseline and subsequent annual visits, gait and balance were assessed using performance-based tasks from which a previously established composite measure of lower limb function was derived. In a general estimating equation analysis controlling for age, education, and gender, a 10 mmHg increment in systolic blood pressure (SBP) was associated with greater decline in lower limb function (estimate of interaction = -6.35 x 10(-3), standard error = 2.49 x 10(-3), p =.011). Thus, on average, lower limb function declined 28.7% faster in persons with an SBP of 160 mmHg than in persons with an SBP of 120 mmHg. This effect was unchanged after controlling for baseline vascular diseases, diabetes, or cognition. However, censoring individuals who developed stroke during the study made the relationship between SBP and change in lower limb function nonsignificant. SBP may be associated with decline in lower limb function in older persons.