en Nursing Original Article <div style="text-align: justify;"><span style="font-size:12px;"><span style="font-family:Times New Roman;"><b>Background:</b> Pain is a prevalent and distressing symptom among intensive care unit (ICU) patients, and inadequate management may lead to serious complications and adverse outcomes. Roy&rsquo;s Adaptation Model provides a structured nursing framework for improving patient adaptation and health outcomes. This study aimed to evaluate the effect of the Roy Adaptation Model on pain levels in ICU patients.<br> <b>Methods:</b> This quasi-experimental study was conducted in 2026 among 100 patients admitted to the ICU in Pakistan. Two comparable ICU wards were randomly assigned to the intervention or control group before participant recruitment. Eligible patients were then consecutively enrolled and assigned to the study groups according to the ICU ward to which they were routinely admitted. Outcome assessors were blinded to group allocation. Patients in the intervention group received care based on the Roy Adaptation Model for 7 days, whereas those in the control group received routine care. Data were collected using the Behavioral Pain Scale (BPS). Data were analyzed using SPSS software version 26. Descriptive statistics (Mean, standard deviation, frequency, and percentage) and inferential statistics (Independent t-test and ANOVA) were applied. A p-value of less than 0.05 was considered statistically significant.<br> <b>Results:</b> Pain scores decreased over the seven-day follow-up period in both groups; however, the reduction was significantly greater in the intervention group than in the control group. For daytime pain, repeated-measures ANOVA showed significant effects of group (F = 16.84, P < 0.001, &eta;p&sup2; = 0.147), time (F = 6.54, P < 0.001, &eta;p&sup2; = 0.063), and the time &times; group interaction (F = 4.72, P < 0.001, &eta;p&sup2; = 0.046). Similar findings were observed for nighttime pain, with significant effects of group (F = 18.32, P < 0.001, &eta;p&sup2; = 0.157), time (F = 6.87, P < 0.001, &eta;p&sup2; = 0.066), and the time &times; group interaction (F = 4.15, P < 0.001, &eta;p&sup2; = 0.040). Independent samples t-tests showed no significant between-group differences during the first two days and nights (P > 0.05); however, pain scores were significantly lower in the intervention group from day 3 to day 7 and from night 3 to night 7 (P < 0.05).<br> <b>Conclusion</b>: The findings suggest that Roy&rsquo;s Adaptation Model may contribute to pain reduction among ICU patients, supporting the potential value of theory-based nursing care in critical care settings. Incorporating this model into routine ICU practice may enhance pain management and facilitate patient adaptation.</span></span></div> Pain, Intensive Care Units, Nursing Care, Roy Adaptation Model 0 0 http://nmj.goums.ac.ir/browse.php?a_code=A-10-2077-12&slc_lang=en&sid=1 Arifa Iran arifairan82@gmail.com 100319475328460018379 0009-0009-4701-8842 No Lahore School of Nursing, The University of Lahore, Lahore, Pakistan Shima Sadat Aghahosseini shimaaghahosseini@yahoo.com 100319475328460018380 100319475328460018380 No Lahore School of Nursing, The University of Lahore, Lahore, Pakistan Rukhsana Nazli rukhsanazi@gmail.com 100319475328460018381 0009-0009-2435-6128 No Lahore School of Nursing, The University of Lahore, Lahore, Pakistan Saifullah Abbas saiff@yahoo.com 100319475328460018382 0009-0005-8218-6199 No Lahore School of Nursing, The University of Lahore, Lahore, Pakistan Farnaz Ahsan farnazahsan562@gmail.com 100319475328460018383 0009-0007-2784-8529 Yes Lahore School of Nursing, The University of Lahore, Lahore, Pakistan