The coexistence of chronic kidney disease and chronic obstructive pulmonary disease, two age‐related conditions, has important clinical and prognostic implications. Respiratory failure is associated with important changes in glomerular and tubulointerstitial function. In contrast, renal failure can affect lung function, mainly by adding a restrictive component or causing complications, such as uremic pulmonary edema and pleural effusion. The effect of age on renal and pulmonary function adds to the complexity of the interplay between the kidney and the lung in these patients. Chronic kidney disease also represents an important risk factor for adverse drug reactions in older chronic obstructive pulmonary disease patients in which multimorbidity and polypharmacy are highly prevalent. Finally, an additive effect of chronic kidney disease and chronic obstructive pulmonary disease might also contribute to the pathophysiology of sarcopenia. Nevertheless, several gaps in our knowledge of the lung–kidney interplay still exist, thus suggesting further basic and clinical research on this topic. Geriatr Gerontol Int 2017; ••: ••–••.