Most dental lasers claim that they can aid in hemostasis during oral and periodontal surgery. To date, there are no studies that compare different lasers' ability to congeal pooled blood. The aim of the study was to see if there was a difference in dental lasers' ability to congeal pooled human blood in vitro. Whole blood was collected from donors, with 0.5 mL (premolar socket volume for all tests) aliquoted into microcentrifuge tubes. Different dental lasers (810-nm diode, 940-nm diode, 1,064-nm Nd:YAG, 2,790-nm Er,Cr:YSGG, 2,940-nm Er:YAG, and 10,600-nm CO2) were applied to the whole blood for 0, 15, 30, and 45 seconds. The sample tubes were centrifuged, and the supernatant color was scored to assess the degree of congealing. Additional samples of blood were tested for time needed for maximum congealing and temperature change. Analysis of supernatant colors showed that there were significant differences in the degrees of congealing for the 810-nm diode, 940-nm diode, and 2,790-nm Er,Cr:YSGG lasers when compared to the 1,064-nm Nd:YAG, 2,940-nm Er:YAG, and 10,600-nm CO2 lasers, but not within those groupings. Additionally, the 1,064-nm Nd:YAG laser increased the temperature of the blood samples more than the other lasers and had a shorter time for maximum congealing. There were differences in the dental lasers' ability to congeal pooled human blood in an in vitro model. Nd:YAG, Er:YAG, and 10,600-nm CO2 lasers were able to achieve a greater degree of congealing at an earlier time point. The Nd:YAG laser produced the most heat and was the fastest to complete coagulation.