Introduction: Critical incident monitoring is important in quality improvement as it identifies potential risks to patients by analyzing adverse events or near-misses. Methods: This study analyses the reported incidents in a tertiary hospital over a 4-year period. Results: A total of 441 incidents were reported out of 98,502 anesthetics performed during the study period. Of these incidents, 67 resulted in no harm caused, 116 with unanticipated ICU admissions and 20 mortalities. The odds of having a critical incident increased with ASA status: from an odds ratio of 2.08 (95% CI: 1.58 to 2.74) for ASA 2 patients compared to ASA1, to OR of 13.70 (5.91 to 31.74) in ASA 5 compared to ASA 1. Critical incidents also have higher odds occurring out of hours (OR 1.7 (1.45 to 2.23) compared to daytime hours (08:00-17:00). They occurred most commonly in maintenance phase (142, 32.7%), followed by induction (120, 27.6%). The most common types of incidents include airway and respiratory (110, 24.9%) followed by drug related incidents (67, 15.2%). Human error was attributed as a significant contributing factor in 276 incidents (61.5%) followed by patient factors in 112 incidents (25.4%). Mitigating factors such as vigilance by staff involved were significant in 136 incidents (30.3%). Conclusion: Higher ASA status appears to be the most important factor associated with actual or potential patient harm in our study. Also significant, was time of incident, with incidents more likely out of hours. Critical incident reporting is a valuable part of quality assurance. We should continue to invest in incident reporting, incident analysis and improvement plans.