Background and aim: Cystic Fibrosis (CF) is a monogenic disorder with heterogeneous phenotypic presentation. In atypical cases, the sweat test may show border-line or normal values and the diagnosis involves the search for mutations in the CFTR gene, clinical features and follow-up. Case report: We present a case of an adolescent boy affected by recurrent acute pancreatitis (AP) started at puberty, with normal sweat values, carrier of compound heterozygosity (I507del+IVS8(5T)). The I507del mutation is a severe CFTR mutation. In contrast, the IVS8(5T) mutation is not associated with clinical cystic fibrosis but, in compound heterozigosity with a more severe mutation, can be causative of mono- or oligo-symptomatic CFTR-related disorders. Conclusion: This is probably the first case report of an atypical CF in a patient with the compound heterozygosity I507del+IVS8 5T. It confirms the challenges and difficulties for diagnosing atypical CF and highlights the role of CFTR mutations in the pathogenesis of idiopathic pancreatitis.