The relative contribution of long-term acute care hospital (LTACH) to short-term acute care hospital (STACH) Medicare patient readmissions is important because of the high acuity of LTACH patients. A retrospective cohort study was conducted to determine the magnitude of LTACH Medicare heart failure (HF) and pneumonia (PN) inpatient readmissions to STACHs within 30 days of LTACH admission and the relative contribution of LTACH patient readmissions to each STACH's total readmissions. Seventy-five for-profit LTACHs and their associated host or primary referral STACHs were studied. An average of 8% HF and 8% PN LTACH Medicare inpatients were readmitted to host or primary referral STACHs within 30 days of admission, representing 0.4% and 0.8% of the total number of HF and PN Medicare patients, respectively, readmitted to the STACHs in fiscal year 2010. The low rates of readmission from LTACHs to STACHs suggest an appropriate level of care for the LTACHs studied.