The aim of this study was to investigate the collagen matrix in recurrent inguinal hernias. Total ribonucleic acid (RNA) was extracted from skin fibroblasts of three groups (control group I = healthy skin; control group II = plain skin scar; recurrent inguinal hernia group = skin of recurrent inguinal hernias; each n = 5). Reverse transcription-polymerase chain reaction (RT-PCR) and Northern blot analysis were used to investigate the expression of procollagen type I/- III, MMP-1, and MMP-13 mRNAs. Both ratios of procollagen types I to III mRNAs and collagen types I to III were apparently decreased in the recurrent hernia group compared to those of both control groups (p < 0.01). Significant differences were caused by the increase of both procollagen type III mRNA and collagen type III protein synthesis. A concomitant increase of MMP-1 and MMP-13 mRNAs and proteins was also observed in the recurrent hernia group and showed significant differences compared to those of both control groups I and II, respectively (p < 0.01). In conclusion, the decreased ratio of collagen types I to III seems not only to be the result of a relative increase in the levels of type III procollagen mRNA but also may be the result of an increase of MMP-1 and MMP-13. The data of the present study strongly suggest recurrent inguinal hernias to be a disease of the collagen matrix and result in a clearer understanding of the underlying pathophysiology and may support specific therapeutic strategies in hernia surgery (e.g., surgical meshes).