To compare rates of 30- and 90-day hospital readmissions and observation or emergency department (ED) returns of older adults using the University of Pittsburgh Medical Center (UPMC) Health Plan Home Transitions (HT) with those of Medicare fee-for-service (FFS) controls without HT. Retrospective cohort study. Analysis of home health and hospital records from 8 UPMC hospitals in Allegheny County, Pennsylvania, from July 1, 2015, to April 30, 2017. HT program participants (n=1,900) and controls (n=1,300). HT is a care transitions program aimed at preventing readmission that identifies older adults at risk of readmission using a robust inclusion algorithm; deploys a multidisciplinary care team, including a nurse practitioner (NP), a social worker (SW), or both; and provides a multimodal service including personalized care planning, education, treatment, monitoring, and communication facilitation. We used multivariable logistic regression to determine the effects of HT on the odds of hospital readmission and observation or ED return, controlling for index admission participant characteristics and home health process measures. The adjusted odds of 30-day readmission was 0.31 (95% confidence interval (CI) = 0.11-0.87, P = .03) and of 90-day readmission was 0.47 (95% CI=CI = 0.26-0.85, P = .01), for participants at medium risk of readmission in HT who received a team visit. The adjusted odds of 30-day readmission was 0.29 (95% CI = 0.10-0.83, P = .02) for participants at high risk of readmission in HT who received a team visit. The adjusted odds of 30-day observation or ED return was 1.90 (95% CI = 1.28-2.82, P = .001) for participants at medium risk of readmission in HT who received a team visit. The HT program may be associated with lower odds of 30- and 90-day hospital readmission and counterbalancing higher odds of observation or ED return. J Am Geriatr Soc 67:156-163, 2019.