Background. High-producer TGFβ1 genotypes are associated with severe lung disease in cystic fibrosis (CF), but studies combining IL-8, TNFα-, and TGFβ1(+genotype) levels and their impact on CF lung disease are scarce.Aim. Assessing the relationship between TGFβ1, IL-8, and TNF-αand lung disease in CF in an exacerbation-free interval.Methods. Twenty four patients delta F508 homozygous (median age 20.5 y, Shwachman score 75, FEV1(%) 83) and 8 controls (median age 27.5 y) were examined. TGFβ1 was assessed in serum and induced sputum (IS) by ELISA, for IL-8 and TNF-αby chemiluminescence in IS and whole blood. Genotyping was performed for TGFβ1 C−509T and T+869C utilizing RFLP.Results. TGFβ1 in IS (CF/controls median 76.5/59.1 pg/mL,P<0.074) was higher in CF. There was a negative correlation between TGFβ1 in serum and lung function (LF) (FEV1 (r=−0.488,P=0.025), MEF 25 (r=−0.425,P=0.055), and VC (r=−0.572,P=0.007)). Genotypes had no impact on TGFβ1 in IS, serum, and LF. In IS TGFβ1 correlated with IL-8 (r=0.593,P<0.007) and TNF-α(r=0.536,P<0.018) in patients colonized by bacteria with flagellin.Conclusion. TGFβ1 in serum not in IS correlates with LF. In patients colonized by bacteria with flagellin, TGFβ1 correlates with IL-8 and TNF-αin IS.