BACKGROUND: To let the early elderly live well, understanding how lifestyle and psychosocial factors related to a decline in competence in daily living is important. METHODS: We investigated the associations between lifestyle and psychosocial factors at age 64 years and a decline in the Tokyo Metropolitan Institute of Gerontology Index of Competence score of ≥ 2 points at age 70 years among the participants in comprehensive medical check-ups living in a city in Japan. Multivariable logistic regression analyses were performed separately for men and women. RESULTS: Of the 1113 eligible men and 1203 eligible women, 110 men and 80 women showed a deteriorated competence in daily living during the 6 years. In men, risk was increased with ≥ 2 nighttime awakenings (multivariable odds ratio [mOR] 2.14, 95% confidence interval [CI] 1.19-3.86) and living alone (mOR 4.68, 95% CI 1.22-18.0), whereas risk was significantly decreased with a medium or fast gait (mOR 0.37 and 0.21, 95% CI 0.21-0.67 and 0.08-0.58) and high academic achievement (mOR 0.32 and 0.43, 95% CI 0.19-0.53 and 0.25-0.72). In women, risk was decreased with high life satisfaction (mOR 0.39, 95% CI 0.16-0.91) and participation in community activities (mOR 0.50, 95% CI 0.29-0.86) but increased with depressive mood (mOR 1.86, 95% CI 1.09-3.18). CONCLUSION: Living alone for men and low life satisfaction for women at age 64 years were markedly associated with the risk of a subsequent declining competence in daily living.