The article presents the modern pharmacotherapy of coincident two common diagnoses: chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). From the clinical point of view, the main doubts and controversies are related to β-blockers. Non-selective β-blockers decrease FEV1. The fears of the use of cardioselective β-blockers are unjustified: retrospective observations indicate that they have a neutral or advantageous effect on the decrease of COPD exacerbation frequency. β-blockers may prevent arrhythmogenic and ischaemic incidents during the intensification of inhaled β2-agonist therapy. The highest cardioselectivity is represented by nebivolol. It is deemed that cholinolytics and β2-agonists with prolonged activity cause ventricular and supraventricular arrythmias. However – attention should be paid to other coexisting arrhythmogenic factors: the erroneous use of theophylline, pulmonary embolism, hypokalaemia, hypomagnesaemia, hypoxaemia, chronic kidney disease, and the COPD exacerbation itself. At last magnesium citrate – the element recommended both by heart and lung specialists.