In an attempt to improve the quality of the breast FNA specimens we instigated a continuing audit of this procedure in this hospital. All FNAs since 1990 have had the following recorded: mode of aspiration, e.g. freehand or image guided, patient presentation (screening or symptomatic), patient diagnostic category, cytological diagnosis and final histological diagnosis. Aspirator performance was assessed by means of the inadequate aspiration rate (IR) of FNAs performed on patients with a final diagnosis of cancer (FDC) and diagnostic category A patients (clinically or radiologically malignant lesions). An ongoing annual review of the performance of all the aspirators was undertaken, all of whom received individual feedback. Counselling and further training were offered where indicated by poor performance. Over the period 1990-1995 a total of 13537 FNAs were performed by 27 aspirators. The IR on category A and FDC cases over this period was 16.0% and 18.1%. The best performance achieved by an aspirator in a calendar year was an IR of 3.6% with no inadequate specimens in either FDC or category A lesions, and the best performance over the entire period was an average IR of 11.75% and 14.25% for FDC and category A groups, respectively. The overall IR on category A patients ranged from 15.9% to 23.8% and on FDC cases from 12.2% to 21.7%. There was a significant improvement in individual junior aspirator performance when their first year was compared with their last year on the unit. In some cases a deterioration in intra-aspirator performance was observed, from an IR of 6% to 33%. The overall IR rate of the unit remained stable for FDC patients, 15.5% in 1990 compared with 15.1% in 1995. This appeared to be largely due to a high proportion of the aspirations being performed by experienced personnel with consistent IRs. However, concealed within the overall rate there were some poor performers who benefited from counselling and/or further training. These results indicate an important role for audit in identifying poor aspirators who benefit from targeted training and advice, thereby improving the quality of FNA specimens, and ultimately patient care.