Strength training has been reported as a potentially useful exercise to improve psychological aspects in the elderly, but its effects remain controversial. This study investigated the effectiveness of strength training conducted twice a week for 12 weeks for improving health-related quality of life (HRQOL) and executive cognitive function. The study was a single-blind randomized controlled trial with assessments before and after intervention. HRQOL and executive function were assessed using the SF-36 Health Status Survey and a computerized neuro-cognitive assessment using task-switch reaction time trials, respectively. Subjects comprised 119 participants > or =65 years old, randomized to either strength training (n=65) or health education classes (controls, n=54). The strength training program was designed to strengthen the large muscle groups most important for functional activities and to improve balance. The effects of the intervention on the eight dimensions of the SF-36 in the control and training groups were analyzed. Only the mental health scale of the SF-36 was significantly improved for the training group compared with controls after 12 weeks. Task-switch reaction time and correct response rate remained unchanged. Short-term strength training might have modest positive effects on HRQOL, although this training period may not be sufficient to affect executive function in relatively healthy older people.