Aims: Pulmonary infections are more frequent in and associated with higher mortality in Cystic Fibrosis-Related Diabetes (CFRD) patients compared to CF patients without CFRD. Hyperglycaemia can lead to a higher vulnerability for infections. Aim of the study was to test whether the infection rate in well-controlled CFRD patients was similar to that in CF patients without CFRD. Methods: This is a retrospective six-year cohort analysis on a consecutive series of 138 CF patients. They were categorized in two groups with CFRD or without CFRD. Pulmonary infection frequency was defined as the number of intravenous (IV) antibiotic treatments. Clinical factors associated with infection frequency were collected. Results: CFRD was diagnosed in 54 (39%) CF patients of whom 44 (81%) achieved target value for glycaemic control (HbA1c 7.0% (≤53 mmol/mol)). Median frequency of IV antibiotics was 0 without CFRD and 3 episodes in patients with CFRD (rate ratio (RR) 2.9 (95% CI 1.6-5.2)). Multivariate analysis showed that frequency of IV antibiotics was significantly related to Pseudomonas aeruginosa colonization (RR 3.7) and lower lung function at baseline (RR 0.97) but not to CFRD by itself. Conclusions: In this cohort with overall strict glycaemic control, the frequency of IV antibiotics use was related to chronic infection and impaired lung function at baseline, but not to CFRD by itself. Although this study in itself does not prove beneficial effect of strict glycaemic control, it does emphasize the potential role of glycaemic control on infection frequency in CF patients.