Mutations in the p53 tumor suppressor gene, located on chromosome 17p, are known to be the most frequent genetic alterations found in human cancers. We used the polymerase chain reaction (PCR) followed by the single-strand conformation polymorphism (SSCP) analysis to screen for mutations of the p53 gene in patients of the European Saar-Lor-Lux area with colorectal cancer at various developmental stages. While we detected no mutations in all of 16 early-staged colonic polyp samples, we revealed 7 (13.7%) transition point mutations in exons 5 to 9 of the p53 gene in 51 late-staged colorectal tumours. These results show that the PCR-SSCP analysis technique provides both a sensitive and rapid method for the genetic staging of colorectal samples and confirm previous reports that p53 mutations are usually associated with an advanced development of colorectal cancer characterized by the transition from adenoma to carcinoma.