Background The versatility of transforaminal lumbar interbody fusion (TLIF) allows fusion at any level along with any necessary canal decompression. Unilateral TLIF with a single interbody device and unilateral pedicle fixation has proven effective, and minimally invasive techniques have shortened hospital stays. Reasonable questions have been raised, though, about whether same-day discharge is feasible and safe after TLIF surgery. Questions/purposes We determined, in a high-volume spine practice, what proportion of patients having one- or two-level minimally invasive unilateral TLIF go home on the day of surgery or stay longer and compared the two groups in terms of outcome scores (VAS scores for back and leg pain, Waddell-Main Disability Index), complications, and hospital readmissions. Methods We retrospectively studied all 1005 patients who underwent 1114 minimally invasive unilateral TLIF procedures by one surgeon between March 18, 2003, and April 12, 2013. For the first 43 months, Medicare patients (65 years or older) were not offered same-day discharge. All other patients were offered the chance to be discharged home on the same day if they felt well enough. Followup data were for 3 months. VAS scores for back and leg pain and Waddell-Main Disability Index were recorded in a prospectively maintained database and readmissions were ascertained by chart review. Data were available on 100% of discharges, 95% of preoperative outcome scores, and 81% of outcome scores out to 3 months. Results Of the 1114 procedures, 808 went home the day of surgery, resulting in a 73% same-day discharge rate. Mean differences in outcome scores from preoperatively to 3 months were similar between groups, except for a difference in VAS lower leg pain in hospital stay patients, which was of borderline statistical and unlikely clinical significance (3.3 versus 2.7, p = 0.05). The only important differences between groups were slightly more medical complications and readmissions for patients 65 years and older who stayed in hospital overnight (3.9% versus 0%, p