Idiopathic chronic and acute recurrent pancreatitis (IP) have been associated with mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Mutations in the serine protease inhibitor Kazal 1 (SPINK1) have been described in some idiopathic chronic patients and it has been suggested that mutations in this gene could be responsible for a loss of trypsin inhibitor function. In this study, the 5'UTR region, and the four exons and exon-intron boundaries of the SPINK1 gene in 32 IP patients have been analyzed. Three IP patients (9.3%) and one control/100 carried the N34S mutation of the SPINK1 gene (Fisher's exact test, P=0.044). No other mutation that could be associated with an altered function of the SPINK1 protein was observed. The N34S mutation was present in two patients who carried the CFTR-IVS8 5T variant and in one who carried the L997F variant in the CFTR gene. The association of SPINK1 with CFTR gene mutations in IP patients is statistically significant (3/32 IP cases and 0/100 control individuals carrying mutations in both genes; Fisher's exact test P=0.01).