The purpose of this study was to report 30 cases of missed lung cancers and describe characteristics of each case. Reasons for misdiagnosis were analyzed from the report. Each radiograph was subsequently reviewed by a panel of two experts who quantified several parameters regarding image analysis and film quality. Lesions were not described in 67% of the cases and were misinterpreted as benign processes in 33% of cases. Comparison to previous chest radiographs and clinical information were seldom available on the report. Size of the lesions varied between 1 and 7 cm, location was primarily apical and paramediastinal, normal anatomy was highly or moderately complex in 87%, and distracting lesions were present in 63% of the cases. Image quality was considered perfect in 3 cases only. Among all the factors responsible for missed lung cancer, certain factors can be improved as film quality, comparison with previous radiographs, and better awareness of clinical information.