AimThis study aimed to explore the association between multimorbidity patterns with/without frailty and future mortality among Taiwanese middle‐aged and older adults through a population‐based cohort study design.MethodsData were collected from the Taiwan Longitudinal Study on Aging. The data were obtained from Wave 3, with the multimorbidity patterns in the years of 1996 being analyzed through latent class analysis. Frailty was defined using the modified Fried criteria. The association between each disease group with/without frailty and mortality was examined using logistic regression, with the reference group as the Relatively healthy group without frailty. Survival analysis was performed using Cox regression, and the follow‐up period of mortality was from 1 January 1996 to 31 December 2012.ResultsA total of 4748 middle‐aged and older adults with an average age of 66.3 years (SD: 9.07 years) were included. Four disease patterns were identified in 1996, namely the Cardiometabolic (21.0%), Arthritis‐cataract (11.9%), Relatively healthy (61.6%), and Multimorbidity (5.5%) groups. After adjusting for all covariates, the Relatively healthy group with frailty showed the highest risk for mortality (odds ratio: 3.66, 95% confidence interval [95% CI]: 2.24–5.95), followed by the Cardiometabolic group with frailty (odds ratio: 3.58, 95% CI: 1.96–6.54), Multimorbidity group with frailty (odds ratio: 2.28, 95% CI: 1.17–4.44), Multimorbidity group without frailty (odds ratio: 1.44, 95% CI: 1.01–2.04), and the Cardiometabolic group without frailty (odds ratio: 1.24, 95% CI: 1.04–1.49).ConclusionsFrailty plays an important role in mortality among middle‐aged and older adults with distinct multimorbidity patterns. Middle‐aged and older adults with a relatively healthy multimorbidity pattern or a cardiometabolic multimorbidity pattern with frailty encountered dismal outcomes. Geriatr Gerontol Int 2023; ••: ••–••.