One hundred and forty patients underwent 142 brushings and conventional biopsies of suspected malignant lesions of the lung through a fibreoptic bronchoscope. Both samples were taken from the same area. One hundred and three patients showed positive results on brushing and 90 on biopsy. Thirty-nine diagnoses were negative on brushing and 52 on biopsy. A correct cell typing was obtained in 105 of 109 diagnoses of malignancy. Final diagnoses showed 118 malignant lesions and 22 benign conditions. False positives were respectively, 2 on brushing and 1 on biopsy, while false negatives were 17 on brushing and 30 on biopsy. Brushing showed higher sensitivity (85.5%) and accuracy (86.6%) than biopsy. A combination of the two techniques gives an accuracy rate of 94.3%.