Eighteen radiologists failed to detect 27 potentially resectable bronchogenic carcinomas revealed retrospectively on serial chest radiographs. Most of the cancers were in an upper lobe (n = 22 [81%]), especially the right upper lobe (n = 15 [56%]). More of the cancers were in women (n = 18 [67%]) than in men (n = 9 [33%]). The mean diameter of the missed lesions was 1.6 cm +/- 0.8 (range, 0.6-3.4 cm). Only two lesions (7%) were well defined around their entire extent. A lateral radiograph (available for 23 patients) revealed the missed lesion better than the posteroanterior radiograph in four patients (17%). Six consultant radiologists, who were biased by knowledge that the cases were of missed bronchogenic carcinoma, were individually shown the radiographs in 22 of the cases. Each consultant missed a mean of 26% (5.8 +/- 1.7) of the lesions. At least one of the six consultants missed the lesion in 16 (73%) of the cases. The predominant characteristics of radiographically missed and potentially resectable bronchogenic carcinomas were difficulty in radiographic detection, female gender, and location in an upper lobe, especially on the right side.