IntroductionPreoperative assessment using widespread laboratory investigations and ancillary tests as preoperative screening may be unnecessary and lead to an economic burden. This study aimed to determine the routine preoperative investigations performed in a tertiary care teaching hospital in the Caribbean that could be categorized as unnecessary and the costs incurred for these tests. MethodsPatient and surgery-specific data were collected prospectively from adult elective surgery patients over a three-month period. Surgical intensity, American Society of Anesthesiologists (ASA) grade and the National Institute for Health and Care Excellence (NICE) (UK, 2016) Clinical Guideline for Preoperative Investigations were used to determine which tests to deem unnecessary. The overall economic burden of unnecessary testing was assessed. ResultsData were prospectively collected from 636 patients during the study period. Sixty-four percent of the preoperative investigations performed were deemed unnecessary. The money spent on these unnecessary investigations amounted to $44,622. When extrapolated, this can amount to approximately $178,488 per annum. This represented 59% of the total money spent on the overall preoperative investigations performed. Relatively healthier patients (ASA I and II) had a significantly higher number of unnecessary investigations performed. ConclusionThis study found that the majority of preoperative investigations performed routinely may be deemed unnecessary. This results in a huge economic burden on the healthcare system. There is a need to update and strictly implement clinical guidelines for preoperative investigations.