Diagnostic laboratory tests are frequently overused in healthcare entities, leading to an increased strain on laboratory resources, additional workload, and wastage of resources. Continuous monitoring of test ordering behavior is crucial to evaluate clinical necessity. This cross-sectional study aimed to estimate the necessity of ordering clinical chemistry tests in the cardiology clinic of a tertiary center in Saudi Arabia. We retrieved medical records of patients diagnosed with cardiovascular problems admitted at the cardiology clinic in 2020. The frequency and percentages of the ordered tests were calculated upon admission and follow-up, and the difference between necessary and unnecessary tests was compared for each category. Test ordering assessment included cardiac, renal, and liver functions, blood gases, thyroid and diabetic profile, iron indices, hormones, water and electrolytes, and inflammatory markers. The results showed a large number of clinical chemistry tests ordered without clinical necessity. While the number of necessary tests was significantly higher than that of unnecessary tests, 21% of the tests ordered between June-December 2021 at the center were unnecessary. Further studies are necessary to identify driving factors and develop strategies to reduce the overutilization of diagnostic laboratory tests in clinical practice. Eliminating this phenomenon will reduce the risk of unnecessary medical interventions and associated costs, improve patient outcomes, and reduce the overall burden on the healthcare system.