Minimally invasive video-assisted parathyroidectomy (MIVAP) was introduced in 1997 for the treatment of sporadic primary hyperparathyroidism (sPHPT). The study aim was to review the entire series of patients operated on in order to analyse the learning curve of this procedure.Between February 1997 to January 2001, 185 patients underwent MIVAP. All these patients were divided into three groups: group A (GA) included 63 patients operated on between February 1997 and September 1998; group B (GB) 64 patients operated on between October 1998 and January 2000; Group C (GC) 64 patients operated on between January 2000 and January 2001. Mean operative time, complications and conversions rates of the three groups were compared.The three groups were well matched for age and gender. Mean operative time was significantly shorter in patients of GC (28.3 +/- 13.6 min) when compared with GA (62.3 +/- 24.6 min) and GB (48.4 +/- 18.1 min). Conversion was required in 3 cases of GA (4.8%), in 8 cases of GB (12.8%) and in 4 cases of GC (6.5%). One transient postoperative recurrent nerve palsy and 4 cases of transient postoperative hypocalcemia were observed among patients of GA. No complications were registered in the other groups.This study shows that with increasing experience, the operative time of MIVAP was dramatically reduced, as well as postoperative complications rate. The higher percentage of conversion in groups B and C may be explained by the fact that, with increasing experience, more difficult and ambiguous cases were operated with this technique.