Snoring and apnea are social and medical problems that affect as many as 2% of adult women and 4% of adult men. This study compares collagen distribution and type with the intensity of snoring and the degree of drowsiness following uvulopalatoplasty with CO2 laser and radiofrequency ablation. Fragments were taken from the soft palate by biopsies of 16 uvulopalatoplasty patients and 5 controls, 5 weeks after surgery, and they were stained with Sirius red and observed with polarization microscopy. Photographs were taken, and the type and changes in the amount of collagen before and after surgery were compared. A histological analysis 5 weeks postoperatively in 10 patients showed an increased amount of collagen and replacement of type III collagen with type I collagen. The increase in the amount of collagen after uvulopalatoplasty was significantly larger in patients than in the controls, and all changes from type III to mostly type I collagen occurred in patients who had the surgery. The subjective improvement of both snoring and somnolence is associated with this increase in type I collagen.