We report molecular and clinical analyses in 71 unrelated patients with cystic fibrosis (CF) from Andalusia (South of Spain). Direct mutation analysis of six mutations of the CFTR gene (delta F508, G542X, R1162X, N1303K, W1182X and 1949de184) was performed. The proportion of CF chromosomes with the above-mentioned mutations was 58.5%. Haplotype analysis was performed with the marker/enzyme pairs XV2C/TaqI and KM19/PstI. A particular haplotype has been found associated with each of the studied mutations, while the pooled data for the unknown mutations are not associated with any particular haplotype. This lack of association indicates that there will not be a single predominant mutation amongst the other CF chromosomes. To assess the relationship between genotype and phenotype in these patients, we correlated the pancreatic status and the occurrence of chronic Pseudomona aeruginosa infection with the observed genotype. Pancreatic insufficiency was present in all patients in whom the analyzed mutations were found to be homozygous or compound heterozygous. We also found a higher rate of Pseudomonas colonization in the group of patients in whom the genotype was homozygous or compound heterozygous for the analysed mutations when compared with the group of patients with a different genotype, but the difference was not statistically significant.