The collaborative treatment of Korean medicine (KM) and Western medicine (WM) in Korea has gained prominence since its initiation. However, comprehensive evaluations of patient satisfaction and care effectiveness remain limited. Thus, this study aimed to evaluate patient satisfaction and the need for collaborative KM-WM treatment in the fourth phase of the national pilot project. A multicenter survey was conducted among 321 patients from 15 institutions participating in the fourth phase of the collaborative KM-WM pilot project, spanning from 1 August 2023 to 31 October 2023. Patient satisfaction and needs were assessed using a validated, semi-structured questionnaire with a 5-point Likert scale. Descriptive statistics and hierarchical multiple regression were used in the analysis. The overall satisfaction with collaborative KM-WM treatment was notably high (91.25%). Among the participants, 91.58% indicated the necessity of the collaborative KM-WM pilot project, whereas 90.66% pointed out the need to incorporate inpatient services into collaborative care. Expansion of the pilot project to additional institutions and primary healthcare settings was substantially demanded (85.36% and 80.06%, respectively). Treatment effects (β, 0.344; 95% CI: 0.237-0.451), appropriate treatment time (β, 0.140; 95% CI: 0.051-0.229), medical procedural efficiency (β, 0.227; 95% CI: 0.126-0.328), and promotional activities (β, 0.175; 95% CI: 0.101-0.250) significantly contributed to overall patient satisfaction (each, p < 0.05). The fourth phase of the KM-WM project reflects high patient satisfaction and a substantial need for collaborative treatment. Further research should include longitudinal studies and employ mixed-methods approaches to better understand, evaluate, and improve collaborative KM-WM treatment.