Background <p>A trauma system based on trauma centers was established in Poland only at the beginning of the second decade of the century. The aim of this study was to quantitatively and comparatively assess the functioning of the trauma system in Poland during the postpandemic period, with a particular emphasis on adult trauma center (TC) performance indicators.</p> Methods <p>Since there is no national registry of multiple trauma in Poland, the analysis is based on official public-use datasets. Among the indicators related to trauma centers, the following are available: number of EMT missions to trauma patients, number of trauma patients admitted to EDs, number of patients admitted to TCs, mode of admission (decision of EMT leader or trauma team leader), average length of stay, maximum length of stay, and number of deaths in the TC. Data for the years 2021–2023 from all 16 provinces were obtained. Missing and imprecise data were verified through interviews with the leaders of the individual TCs. Additionally, a review of the literature regarding treatment outcomes in Polish trauma centers was conducted.</p> Results <p>An average of 1,029,615 trauma patients are admitted to EDs each year. The average number of admissions per year to TCs is 4645, i.e., 273 per center, with large regional variations ranging from 21 to 1226 admissions. Only 57% of patients are referred to TCs directly, on the basis of the decision of the EMT leader. The median length of stay is 11–12 days and is relatively constant over the period studied. The overall mortality rate in TCs is estimated at 6%, with wide variation from 0 to 31% across centers. The analysis may be biased with an error resulting from the poor quality of the data obtained.</p> Conclusions <p>The quality of care for patients with multiple organ injuries in Poland varies greatly across regions. There is a high risk of undertriage, largely due to the very stringent admission criteria for trauma centers. This results in a significant disparity in the number of patients admitted, even though the criteria are the same for all centers. The overall number of adult patients admitted to the TC appears to be low considering the overall trauma burden. The current criteria for triage and admission to a trauma center may be misinterpreted, leading to ineffective cooperation between the links of the trauma system. A nationwide trauma registry as a starting database of information for conducting epidemiological studies and developing treatment protocols is urgently needed.</p>