This cross-sectional study compared the healthcare expenditures associated with multimorbidity (having ≥2 chronic conditions) versus no multimorbidity among older United States (US) adults (aged ≥ 50 years) with self-reported pain in the past 4 weeks. This research used data from the 2018 Medical Expenditure Panel Survey. Adjusted linear regression models evaluated group differences in various annual healthcare expenditures. Descriptive statistics indicated multimorbidity was associated with all personal characteristics ( < 0.05) except gender and smoking status ( > 0.05). Multimorbidity had 75.8% greater annual total health expenditures ( = 0.0083), 40.6% greater office-based expenditures ( = 0.0224), 100.6% greater prescription medication costs, ( = 0.0268), yet 47.3% lower inpatient expenditures ( = 0.0158), and 56.6% lower home healthcare expenditures ( < 0.0001) than no multimorbidity. This study found greater healthcare expenditures among older US adults with pain and multimorbidity, which captures the financial burden of comorbidity in this population.