Patients with bilateral knee arthritis are candidates for total knee arthroplasty and may decide between simultaneous (SIMTKA) or staged bilateral TKA (STATKA). Inconsistent outcomes have been reported for SIMTKA and STATKA. This study aims to compare the deep joint infection following SIMTKA and STATKA surgery. The electronic medical records (EHR) from the Optum database (2007-2019) were used to identify TKA patients. The EHR data were available for a geographically diverse population of 5.5 million health plan members who have been successfully linked to the Optum EHR database. Short interval STATKA was defined as having staged surgery within 2 weeks after the first unilateral TKA. The postoperative outcome assessed was deep joint infection six months after surgery. Multivariable logistic regression was developed to investigate association between surgery type and deep joint infection with age, Elixhauser comorbidity score and provider volume adjustment. A total of 6,135 SMITKA and 8,203 two-week STATKA were included in the analysis. SIMTKA were younger (mean 63±8 vs 66±10, p<0.001), with more comorbidities (Elixhauser score ≥4: 21% vs 18.6%, p<0.001), suffering more pain (back pain: 12.8% vs 6.5%, p<0.001; knee pain diagnosis: 44.6% vs 16.9%, p<0.001), and more likely to be treated in facilities with higher volume of TKA surgeries (annual volume: 120±95 vs 114±149). In the multivariable logistic regression, patients who had simultaneous TKA were more likely to suffer from deep joint infection six month after surgery compared to patients having 2-week staged TKA (aOR: 3.4, 95% CI: 2.2, 5.5, incidence: 1.14% vs 0.33%). This study demonstrates that simultaneous TKA is associated with increase risk of deep joint infection compared to 2-week staged TKA. Studies are warranted to investigate the best interval of staged TKA and to compare other surgical outcomes among SIMTKA and STATKA.