Several studies have demonstrated the superiority of the laparoscopic approach in uncomplicated and complicated appendicitis with conflicting results. As a result the role of laparoscopy in the management of appendicitis in general and complicated or perforated appendicitis, in particular, is still undefined. A retrospective, observational study design was used to analyze multicenter outcomes using the University HealthSystem Consortium database. A 3-year discharge data of all open appendectomy (OA) and laparoscopic appendectomy (LA) procedures from 2006 to 2008 in adult patients older than 18 years for complicated or uncomplicated appendicitis was accessed using International Classification of Diseases, Ninth Revision codes. Data on several surgical outcome measures such as observed mortality, overall patient morbidity, intensive care unit admission rate, 30-day readmission rate, length of hospital stay, and hospital costs were collected from the University HealthSystem Consortium database. Stratification by University HealthSystem Consortium-specific severity of illness groups and disease diagnosis of complicated or perforated and uncomplicated appendicitis was performed. A total of 40,337 appendectomy procedures performed during 2006 to 2008 in adult patients were included in the study. Laparoscopic appendectomy for uncomplicated appendicitis resulted in significantly better surgical outcomes. However, surprisingly, these outcomes resulted in comparable but not significantly reduced hospital costs (7825 ± 6,009 for LA vs 7841 ± 13,147 for OA; P > 0.05). Laparoscopic appendectomy for complicated or perforated appendicitis showed lower mortality, reduced overall morbidity (17.43% for LA vs 26.68% for OA; P < 0.001), relatively less 30-day readmission rate, fewer intensive care unit admissions, significantly shorter length of hospital stay (4.34 ± 4.84 days for LA vs 7.31 ± 9.43 for OA; P < 0.001), and reduced hospital costs (12,125 ± 14,430 for LA vs 17,594 ± 28,065 for OA; P < 0.001) compared with patients undergoing OA. On stratification for severity of illness in both complicated and uncomplicated appendicitis, laparoscopic appendectomy resulted in a greater or comparable clinical benefit than open appendectomy. Comparable clinical benefit was observed in minor severity patients and moderate and major/extreme severity patients showed vastly improved surgical outcomes with the laparoscopic approach. Laparoscopic appendectomy is superior or comparable to open appendectomy in terms of several surgical outcome measures for both uncomplicated and complicated appendicitis, across most illness severity groups. Thus, laparoscopic appendectomy may be the preferred technique, irrespective of appendicitis diagnosis or disease severity.