We subjectively and objectively evaluated 136 patients with socially unacceptable snoring (SUS) or obstructive sleep apnoea syndrome (OSAS) treated with uvulopalatopharyngoplasty (UPPP) after a diagnostic workup by sleep registration (polysomnography, PSG) and sleep endoscopy. Of the 136 patients, there were 88 with OSAS and 48 with SUS. The results of the procedure were considered subjectively to be an improvement in 38 (79%) of the SUS patients and in 74 (84%) of the patients with OSAS. In 36 (40%) of the 88 patients with OSAS, repeating PSG postoperatively was considered unnecessary because of obvious improvement. Of the 52 patients with a measurement after UPPP, a decrease in the apnoea hypopnoea index (AHI) was found in 38 (73%; median decrease: 48%), and AHI dropped below 20 in 32 (62%). The apnoea index (AI) was available in 49 (56%) patients and was reduced in 31 (63%; median decrease: 73%). An overall positive result in the 88 patients with OSAS (combining available data on subjective and objective results) was therefore found in 61 (69%; positive subjective result and AHI <15) or 71 (81%; positive subjective result and decrease in AHI), respectively, depending on the definition. We conclude that after diagnostic workup by sleep registration and sleep endoscopy, the success rate of UPPP increases as compared to historical controls.