Importance: The widespread use of the 7-valent pneu-mococcal conjugate vaccine (PVC7), developed to combat invasive Streptococcus pneumoniae infections, has the potential to influence the prevalence and antibiotic resistance patterns of pathogens associated with orbital complications from acute sinusitis. Given the significant morbidity that may result from inadequate treatment of orbital infections related to acute sinusitis, determining the impact of PCV7 on the bacteriology and drug resistance of the pathogens associated with these infections may provide critical information needed to accurately guide optimal clinical management. Objective: To determine if the characteristics of orbital complications from acute sinusitis in children have changed in the post-PCV7 era. Design: Review of clinical data. Setting: Tertiary care children's hospital. Participants: Patients with a diagnosis of orbital cellulitis and/or subperiosteal abscess from January 1, 1996, to December 31, 2009. Patients with immune deficiency or orbital trauma were excluded. Patients were divided into pre-PCV7 (before 2003 [n=128]) and post-PCV7 (2003 and after [n =145]) groups. Statistical analyses were used to compare the 2 groups. Main Outcome Measures: Differences in patient demographics, signs and symptoms, laboratory study results, computed tomography scan findings, and microbiological analyses between the pre-PCV7 and post-PCV7 groups. Results: A total of 273 children met the inclusion criteria. The post-PCV7 group was older (71.4 months vs 88.8 months [P = .007]) than thepre-PCV7 group. A significant decrease in S pneumoniae and Streptococcus viridans-positive sinus or blood cultures were observed (22.4%vs 0% [P<.001] and 12.24% vs 0% [P = .005], respectively). An increase in Staphylococcus aureus was seen in the post-PCV7 group (20.4% vs 42.37% [P = .02]). Methicillin-resistant S aureus (MRSA) was isolated only in the post-PCV7 group (P = .002). The pre-PCV7 group had a significantly longer hospital stay than the post-PCV7 group (7.15 days vs 5.47 days [P=.004]). Conclusions and Relevance: Although universal PCV7 vaccination has eliminated S pneumoniae as an etiologic pathogen in acute sinusitis complications in this series, there has been a parallel and significant increase in S aureus, including an increase in the prevalence of MRSA associated with orbital infections related to acute sinusitis.