596 Background: Aspirin use has been reported to reduce the pre-op systemic inflammatory response (SIR) in patients with colorectal cancer (CRC). Moreover, an exaggerated post-op SIR, evidenced by C-reactive protein (CRP) concentrations, is associated with poorer short and long term outcomes, highlighting the importance of CRP as a potential therapeutic target for improving outcomes following surgery for CRC. Drugs such as corticosteroids, aspirin and statins may modulate the post-op SIR, but there is little current evidence supporting this hypothesis. Therefore, the aim of the present study was to determine whether pre-op prescription of aspirin or statins modulated the post-op SIR in patients undergoing surgery for CRC. Methods: Included patients were obtained from a prospectively maintained database of CRC resections from a single institution (2010-2014). The relationship between pre-op aspirin and statin prescription and post-op CRP concentrations was examined. Results: 446 patients were included. The majority of patients were > 65 yrs (64%), male (57%) and underwent elective surgery (91%). 120 patients were prescribed aspirin and 187 prescribed statins with 100 patients prescribed both. Patients prescribed aspirin had a reduced post-op SIR particularly on day 3 (p = 0.009), 4 (p = 0.003) and 5 (p = 0.005). This effect was also observed following elective surgery (n = 402) on day 3 (p = 0.014), day 4 (p = 0.009) and day 5 (p = 0.019). Patients prescribed a statin also had a reduced post-op SIR, particularly on days 3 (p = 0.010), 4 (p = 0.006) and 5 (p = 0.017) and also following elective surgery on day 3 (p = 0.039) and day 4 (p = 0.039). The combination of aspirin and statin, compared with none or each on its own, resulted in the lowest post-op SIR, particularly on day 3 (p = 0.015), day 4 (p = 0.006) and day 5 (p = 0.023). Conclusions: Pre-op prescription of aspirin or statins resulted in a reduced post-op SIR following surgery for CRC. Therefore, pre-op use of these medications may be of benefit in improving outcomes, by reducing the post-op SIR – a reported predictor of both long and short term outcomes, following surgery for CRC.