Dyspnea and exercise intolerance are usually attributed to pulmonary disease in sarcoidosis patients. However, cardiac involvement may also be responsible for these symptoms. Data regarding the impact of heart involvement on lung function in cardiac sarcoidosis (CS) is limited.The aim of study was to compare the results of pulmonary function tests (PFTs) in patients with and without heart involvement. We performed a retrospective analysis of PFTs in a group of sarcoidosis patients both with and without heart involvement evaluated by cardiovascular magnetic resonance (CMR) study. The study was performed in the period between May 2008 and April 2016.We included data of sarcoidosis patients who underwent testing for possible CS (including CMR study) at a national tertiary referral center for patients with interstitial lung diseases. All patients had histopathologicaly confirmed sarcoidosis and underwent standard evaluation with PFTs measurements including spirometry, plethysmography, lung transfer factor (TL,CO), and 6-minute walking test (6MWT) assessed using the most recent predicted values.We identified 255 sarcoidosis patients (93 women, age 42 ± 10.7 y): 103 with CS and 152 without CS (controls). CS patients had significantly lower left ventricular ejection fraction (LVEF; 56.9 ± 7.0 vs 60.4 ± 5.4, P < .001). Any type of lung dysfunction was seen in 63% of CS patients compared with 31% in the controls (P = .005). Ventilatory disturbances (obstructive or restrictive pattern) and low TL,CO were more frequent in CS group (52% vs 23%, P < .001 and 38% vs 18% P < .01 respectively). CS (OR = 2.13, 95% CI: 1.11-4.07, P = .02), stage of the disease (OR = 3.13, 95% CI: 1.4-7.0, P = .006) and LVEF (coefficient = -0.068 ± 0.027, P = .011) were independent factors associated with low FEV1 but not low TL,CO. There was a significant correlation between LVEF and FEV1 in CS group (r = 0.31, n = 89, P = .003). No significant difference in 6MWD between CS patients and controls was observed.Lung function impairment was more frequent in CS. Lower LVEF was associated with decreased values of FEV1. Relatively poor lung function may be an indication of cardiac sarcoidosis.