BACKGROUND: Unlike influenza, information on the risk of human metapneumovirus (HMPV) infections in adults with chronic medical conditions (CMCs) is less robust. METHODS: The SHIVERS project (Southern Hemisphere Influenza and Vaccine Effectiveness Research and Surveillance) performed a population-based surveillance of acute respiratory illness hospitalizations in Auckland, New Zealand, from 2012 to 2015. In this analysis, we linked these surveillance data to population-based administrative data to estimate the age- and ethnicity-adjusted risk of HMPV-associated hospitalization during the study period among adults by certain CMCs: chronic obstructive pulmonary disease, asthma, congestive heart failure, coronary artery disease, cerebrovascular accidents, diabetes mellitus, and end-stage renal disease. RESULTS: Overall, HMPV hospitalization rates were significantly higher across all ages and ethnic groups among adults with CMCs than those without any condition. In imputed analysis, the CMC with the highest risk of HMPV hospitalization across age groups was congestive heart failure (incidence rate ratio [IRR] range, 7.0-23.0), followed by coronary artery disease (IRR range, 4.2-9.1) and chronic obstructive pulmonary disease (IRR range, 6.7-11.9) in adults aged ≥50 years. The CMC with the highest risk of HMPV hospitalization was congestive heart failure in Māori/Pacific adults and chronic obstructive pulmonary disease in non-Māori/Pacific adults. Adults with ≥2 CMCs had a higher risk than those without CMCs; the risk varied by age group and ethnicity. CONCLUSIONS: Adults with specific or ≥2 CMCs are at increased risk of HMPV hospitalizations. Age and ethnicity affect this relationship for some CMCs but not all. Such populations may benefit from future HMPV prevention strategies.