IMPORTANCE Although evidence suggests worse outcomes for patients admitted to the hospital on a weekend, to our knowledge, no previous studies have investigated the effects of weekend discharge. OBJECTIVE To determine whether weekend discharge would be associated with an increased rate of 30-and 90-day hospital readmission. DESIGN, SETTING, AND PARTICIPANTS Retrospective review of discharge abstracts from the California Office of State Health Planning and Development from 2012 identifying all patients who underwent abdominal aortic aneurysm (AAA) repair, colectomy, total hip arthroplasty, and pancreatectomy. This study was conducted from January to December 2012. MAIN OUTCOMES AND MEASURES Thirty-and 90-day readmission rateswere compared between patients discharged on a weekend vs weekday. RESULTS Of 128 057 patients, 5225 patients (4.1%) underwent AAA repair; 29 388 (22.9%), colectomy; 91 168 (71.2%), hip replacement; and 2276 (1.8%), pancreatectomy. Overall, 29 883 (23.3%) were discharged on a weekend. Although there were no significant differences with respect to sex, age, race/ethnicity, insurance status, or type of admission, patients discharged on a weekend had shorter length of stays and were less often discharged to a skilled nursing facility. Overall, the 30-day readmission rate was 9.4%after AAA repair, 13.6%after colectomy, 7.5%after hip replacement, and 16.3%after pancreatectomy. Hospital readmission rates were similar for those discharged on a weekend vs weekday after AAA repair (8.8% vs 9.3%; P = .55) and pancreatectomy (17.5%vs 15.9%; P = .40). However, weekend discharge was associated with a lower 30-day readmission rate for patients undergoing colectomy (12.1% vs 14.1%; P < .001) and hip replacement (6.9%vs 7.7%; P < .001). On multivariable analysis, weekend discharge was inversely associated with readmission after colectomy (odds ratio [OR], 0.86; 95%CI, 0.79-0.93) but not AAA repair (OR, 0.93; 95%CI, 0.73-1.19), hip replacement (OR, 0.97; 95%CI, 0.91-1.03), or pancreatectomy (OR, 1.02; 95%CI, 0.76-1.36). Finally, a substantial percentage of 30-day readmissions occurred at a different hospital (AAA repair: 40.5%; colectomy: 25.8%; hip replacement: 32.5%; and pancreatectomy: 19.7%) compared with the index hospitalization. Similar results were seen for 90-day readmissions. CONCLUSIONS AND RELEVANCE Weekend discharge after major surgery is not associated with higher 30-or 90-day readmission rates.