To assess whether chest ultrasound (US) can be useful in the diagnosis of lobar bronchioloalveolar carcinoma, we retrospectively analyzed the US patterns of eight patients with bronchioloalveolar carcinoma presenting with lobar consolidation. For comparison, 15 patients with lobar consolidation of a benign etiology were also analyzed. We found that the US patterns of lobar bronchioloalveolar carcinoma had a characteristic homogeneous, echogenic pattern. The air-bronchograms and air-alveolograms were scarce when compared to benign consolidation. The sensitivity of using these US criteria in discriminating lobar bronchioloalveolar carcinoma was 75%, and the specificity was 93%. We also assessed the yield of US-guided transthoracic cutting biopsies in the diagnosis of lobar bronchioloalveolar carcinoma. The diagnostic rate of the US-guided cutting biopsy was 100%, which was superior to other diagnostic procedures, such as sputum cytology (37%), fiberoptic bronchoscopy with brushing or biopsy (32%) and trans-thoracic needle aspiration cytology (50%). None of the patients developed complications. We conclude that the distinct US pattern for lobar bronchioloalveolar carcinoma is a helpful diagnostic sign, and the US-guided biopsy is a useful approach in the diagnosis of lobar bronchioloalveolar carcinoma.