OBJECTIVE To compare, contrast and analyze the value and limitations of fine needle aspiration (FNA) cytology and core biopsy (CB) in a rural setting. METHODS Retrospective analysis of 100 FNA cytology and 100 CB results of mass lesions from 193 patients matched for age, sex and body organs, and referred for FNA or CB in rural New South Wales, Australia, between September 1990 and May 1996. RESULTS FNA cytology and CB results from 193 patients were analyzed, based on anatomic location and cytologic criteria. Sites included lung, retroperitoneum, liver, breast, kidney, pancreas and ovary. The FNA group contained 6 inadequate, 14 benign, 3 atypical, 6 suspicious and 71 malignant cases, whereas the CB group had 1 inadequate, 24 benign and 75 malignant conditions. The inadequate samples in both groups were due to technical difficulty in obtaining representative material. The indeterminate (atypical and suspicious) group, which was the main pitfall of FNA, contained 4 low grade carcinomas, 3 low grade non-Hodgkin's lymphomas and 2 fibrocystic breast changes. The benign FNA group comprised 8 cysts, 5 inflammatory/reactive conditions and 1 benign tumor/hamartoma, whereas the benign CB group contained 11 cysts, 9 inflammatory/reactive conditions and 4 benign tumors. CONCLUSIONS FNA was comparable to CB at most anatomic sites. CB occasionally offered additional information. This slight advantage was due to the availability of tissue from the first and often the only pass for assessment of architecture and performance of ancillary tests, which obviated the need for further sampling. On-site assessment of the core imprints at the time of the procedure by the highly skilled and experienced interventional cytopathologist was responsible for limiting the number of attempts to one core in most of the instances, therefore minimizing complications. Pathologists are encouraged to become more familiar with the criteria of aspiration cytology, which has proven its validity in the new cost-conscious environment. Despite the recent surge in the popularity of core biopsy, FNA cytology, when practiced in a multidisciplinary setting, with involvement of pathologists, radiologists and clinicians, is an extremely accurate test with very high sensitivity, which approaches that of surgical pathology, and specificity very similar to that of frozen section. FNA has a positive predictive value for a malignant diagnosis of almost 100%. FNA is a well-tolerated, relatively noninvasive test with a very low risk of complications.