Sleep disturbance is a common symptom in institutionalized older adults that reduces their quality of life and may contribute to progression of cognitive impairment. While we found that a 7-week combination of resistance training, walking and social activity significantly improved sleep in institutionalized older adults compared with a usual care control group, no one to our knowledge has determined the acute effects of resistance training on same-day sleep in this population. Given the effort required to promote exercise adherence in institutionalized older adults and to obtain a positive training effect, understanding of the acute effects of resistance training on same-day sleep architecture should be elucidated, especially with respect to unintended consequences. This secondary data analysis assessed if resistance training altered the same-day sleep architecture in institutionalized older adults. Forty-three participants (age 81.5 ± 8.1 years, male = 17, female = 26) had two attended overnight polysomnography tests in their rooms for sleep architecture analysis; one polysomnography with same-day resistance training, one without any resistance training. Resistance training consisted of chest and leg press exercises (three sets, eight repetitions, 80% predicted one-repetition maximum). There were no significant changes in sleep architecture between either polysomnography nights; sleep efficiency (P = 0.71), time in non-rapid eye movement stages (P = 0.50), time in rapid eye movement stages (P = 0.14), time awake (P = 0.56), time until sleep onset (P = 0.47), total sleep stage shifts (P = 0.65) or rapid eye movement sleep stage latency (P = 0.57). Our results show no acute same-day effects of resistance training on sleep architecture in institutionalized older adults. Clinical Trial Registration ClinicalTrials.gov Identifier: NCT00888706.