Background: Surgical site infection (SSI) remains a major cause of morbidity after colorectal resection. Pulse lavage irrigation may reduce bacterial load before wound closure, but its effectiveness in colorectal surgery is uncertain. This study evaluated the association between intra operative pulse lavage and postoperative SSI. Method: A single centre retrospective cohort study was performed of adults undergoing colorectal resection at Cairns Hospital (QLD, AUS), between Jan 2019 and Oct 2025. Patients were divided into pulse lavage and standard irrigation groups. The primary outcome was 30 day SSI. Secondary outcomes were any postoperative surgical complication, re-operation, 30 day readmission, length of stay and 30 day mortality. Groups were compared using χ² or Fisher’s exact tests and t tests or Mann–Whitney U tests, as appropriate. Unadjusted relative risk (RR) and odds ratio (OR) estimates with 95% confidence intervals (CIs) were calculated. Results: A total of 574 patients undergoing colorectal resection were included; 39 received pulse lavage and 535 had standard irrigation. The mean age was 66.5 years, 41.5% were female, mean BMI was 27.5 kg/m², 62.5% had ASA ≥3, 17.2% were emergency surgery and 71.9% were laparoscopic surgeries. Baseline characteristics were similar between groups. SSI rate was 5.9% (34/574). No SSI was observed in the pulse lavage group (0/39) compared with 34/535 (6.4%) in the standard irrigation group (RR 0.19, 95% CI 0.01–3.11; OR 0.18, 95% CI 0.01–3.06; p = 0.16). In the propensity score–matched cohort (39 pulse lavage; 117 matched controls), SSI rates were 0.0% versus 6.0% (RR 0.20, 95% CI 0.01–3.37; p = 0.19). No significant difference in secondary outcomes between groups. Conclusion: In this colorectal surgery cohort, pulse lavage was associated with no observed SSIs and a non significant trend towards reduced infection. These findings support larger, prospective studies to clarify the impact of pulse lavage on SSI.