Functional tests have been performed to predict cognitive decline in postmenopausal women and may be an important tool to identify early reductions in cognitive performance in this population. However, it is still unclear which functional test is more sensitive for detecting cognitive decline in the investigated sample. The aim of this study was to verify the association between functional performance and cognitive function in postmenopausal women and to analyze whether the gait speed of 400 meters (400wt) and Timed Up and Go (TUG) tests are predictors of cognitive function in this sample. One hundred and twenty eight postmenopausal women (60.8 ± 7.9 years) participated in this cross-sectional study. Body composition was assessed using Dual Energy X-ray Absorptiometry (DXA), functional performance by the TUG and 400wt tests, cognitive performance by the Montreal Cognitive Assessment (MoCA) test and muscle strength by maximum voluntary isometric contraction (MVIC) in lower limbs. An association between functional performance and cognitive function was observed in middle-aged postmenopausal women. The TUG test was associated with the MoCA test (B = -0.79; SE = 0.29; p = 0.008). However, no association was observed between 400wt with the MoCA test (B = 3.03; SE = 1.92; p = 0.117). These results show that the TUG test is a good predictor of cognitive decline in postmenopausal middle-aged women.