BACKGROUND Imaging-guided core needle biopsy is a minimally invasive and effective tissue sampling method. Touch imprint cytology (TIC) can provide immediate on-site preliminary interpretation and adequacy of core needle biopsy. We investigated on-site TICs' impact on minimizing the number of core needle biopsy passes required for diagnosis. METHODS Five hundred and sixty imaging-guided CNBs with TICs including 393 malignant lesions, 136 benign lesions, 29 nondiagnostic specimens, and 2 atypical lesions were reviewed for adequacy, preliminary interpretation, final histological diagnosis, and the number of core needle biopsy passes. RESULTS The adequacy rate determined by on-site TICs was 76%, with 50% for benign lesions, and 88% for malignant lesions. The correlation rate between TICs' preliminary interpretation and histological diagnosis was 91%, with 100% for benign lesions and 89% for malignant lesions. In malignant lesions, the adequacy rate was lowest in cases with sarcomas (58%), followed by hepatocellular carcinoma and renal cell carcinoma. When all cases are stratified by locations, the adequacy rate determined by on-site TICs was lowest in lesions from soft tissue (45%), followed by pelvic mass or kidney. The average number of cores was 4.1 per case in adequate specimens, significantly lower than that in specimens without TICs. In contrast, the average number of cores was 7.1 per case in inadequate specimens, significantly greater than that in specimens without TICs. CONCLUSIONS On-site TICs showed its usefulness in reducing the number of cores required for adequate diagnostic materials. In the meantime, TICs accurately provided preliminary interpretations, especially in adequate malignant carcinoma cases.