To assess if the effectiveness of biopsy sampling, whose usefulness is widely recognized, can be influenced by different cutting mechanisms, we compared four different types of needles (A, B, C, D) in 76 patients, each needle being of the same length (15 cm) and calibre (18 G) but with different tip shapes. Forty biopsy samples were obtained with each type of needle for a total of 160 samples in 76 patients; 61 samples were acquired under CT guidance and 99 under US guidance. The results were subdivided in 6 categories based on biopsy result: PI (diagnosis histotype in malignant lesions), PN (diagnosis of malignancy in neoplastic lesions), P (correct diagnosis in benign lesions), S (suspicion of neoplastic lesion), E (misdiagnosis), NI (insufficient material). The results, respectively, for each needle type are: 32.5%, 30%, 2.5%, 7.5%, 12.5% and 15% with needle A; 35%, 30%, 7.5%, 0%, 15% and 12.5% with needle B; 27.5%, 17.5%, 10%, 7.5%, 22.5% and 15% with needle C; 30%, 15%, 7.5%, 15%, 17.5% and 15% with needle D. The sensitivity and specificity for each needle type were, respectively, 84.4% and 85.29% for needle A; 86.66% and 88.57% for needle B; 70% and 73.52% for needle C; 77.41% and 79.41% for needle D. No statistically significant difference was found in the effectiveness of the four needles (chi 2); on the contrary, lesions's size can affect sampling quality.