Study Type Therapy (case series) Level of Evidence4 What's known on the subject? and What does the study add? New techniques and instrumentation in laparoscopy including the use of single-port' devices and natural orifice transluminal endoscopic surgery have been proposed to reduce the invasiveness of these procedures. The introduction of small laparoscopic instruments (<3mm) continues to further the field. To date, mini-laparoscopic instruments have been used in many urological procedures, e.g. pyeloplasty in the paediatric population. However, data of pure mini-laparoscopic pyeloplasty (mLP) for the treatment of pelvi-ureteric junction obstruction in the adult population are lacking. In a selected adult population mLP is feasible and safe. Perioperative and 1-year functional results are comparable with those of standard LP, while cosmetic results of mLP are more appreciated by the patients. OBJECTIVE center dot To evaluate perioperative and cosmetic results after pure mini-laparoscopic pyeloplasty (mLP) compared with standard LP (sLP) in an adult population. PATIENTS AND METHODS center dot From April 2009 to June 2010, 12 patients underwent mLP for pelvi-ureteric junction (PUJ) obstruction (PUJO). For comparison, 24 patients that had previously undergone sLP were pooled from our institutional database. center dot All patients were assessed preoperatively with physical examination, abdominal ultrasonography, intravenous urography or computed tomography and renal scintigraphy (RS). In all cases, an Anderson-Hynes transperitoneal approach was used. center dot After surgery, cosmetic results were assessed using a Patient Scar Assessment Questionnaire (PSAQ), and RS measured reconstructive success at 1-year after LP. center dot Demographic and perioperative variables were recorded. Groups were compared using chi-squared and Wilcoxon-Mann-Whitney tests (P < 0.05 was considered significant). RESULTS center dot Baseline characteristics were similar between the groups. There were no differences in operative duration or blood loss. One mLP required conversion to sLP due to minor bleeding. center dot Analgesic consumption and the pain visual analogue scale scores were not significantly different between the sLP and mLP cohorts. center dot The average postoperative hospital stay for the mLP group was significantly shorter than that for the sLP group (P= 0.024). center dot Complication and success rates between the groups were not significantly different. center dot PSAQ scores showed that mLP patients were significantly more satisfied with their cosmetic result. CONCLUSIONS center dot mLP appears to be safe, feasible and effective in the treatment of PUJOs. center dot Cosmetically, mLP is better than sLP.