Abstract Background: Spirometry is an important test for the diagnosis of respiratory diseases, yet it is underused especially in older adults. Several predictors of good-quality spirometry in this age group have been reported, based mainly on in/outpatients of geriatric and/or respiratory units. Aims: This study aims to assess predictors of poor-quality spirometry in community-dwelling older adults from two primary care cohorts in Russia and Belgium. Methods: Spirograms from two population-based cohort studies in Russia (CRYSTAL) and Belgium (BELFRAIL) were assessed in accordance with the American Thoracic Society/European Respiratory Society (ATS/ERS) acceptability and repeatability criteria and grouped into good and poor quality. Multivariable analysis assessed the association of poor-quality spirometry with socio-demographics, functional dependency, physical and mental functioning and co-morbidities. Results: In all, 43.3% of the 522 BELFRAIL participants (84.71±3.67 years old) and 57.7% of the 605 CRYSTAL participants (75.11±5.97 years old) achieved all ATS/ERS acceptability and repeatability criteria. In both cohorts, those with poor-quality spirometry had lower cognitive function (mini-mental state examination (MMSE) ⩽24). After adjustment in multivariable analysis, MMSE ⩽24 had an odds ratio for poor-quality spirometry of 1.33 (95% CI=0.78–2.28) in the BELFRAIL and 1.30 (95% CI=0.88–1.91) in the CRYSTAL cohort. Conclusions: In community-dwelling older adults, including those over 80 years old, impaired cognition measured by the MMSE may not be an independent predictor of poor-quality spirometry. Further research is needed in this area, and spirometry should be used more often in older adults in primary care.