This study applied the stochastic frontier cost function with inefficiency effects to estimate the association between quality of care and cost efficiency in institutional long-term care wards for the elderly in Finland. We used several clinical quality indicators for indicating adverse care processes and outcomes, based on the Resident Assessment Instrument (RAI)/Minimum Data Set (MDS). Average cost inefficiency among the wards was 22%. We found an association between the clinical quality indicators and cost inefficiency. Higher prevalence of pressure ulcers was associated with higher costs, whereas the higher prevalence of use of depressants and hypnotics increased inefficiency.