Lymphatic plastic bronchitis (PB) most commonly occurs in children with congenital heart disease as a result of secondary pulmonary lymphatic flow disorder (PLFD). However, PB caused by primary PLFD is rare. The clinical symptoms of lymphocytic PB are nonspecific; thus, the diagnosis may be long delayed, especially in the absence of chylothorax. We made a retrospective analysis of two children diagnosed with PB due to primary PLFD, in order to contribute to further understanding of these disorders. Patient 1, an eight-year-old boy, presented with chronic productive cough and expectorated milky-white mucous plugs accompanied by intermitted wheezing for one year. Patient 2, a nine-month-old girl, presented with episodes of acute respiratory distress with expectoration of milky-white bronchial casts for four months. There was no obvious evidence of infection in either child. Bilateral thickening of bronchovascular bundles and interlobular septal, as well as multiple patchy ground-glass opacities were seen on chest computed tomography (CT) in both patients. Lymphangioscintigraphy demonstrated pulmonary lymph reflux in both patients and slowed lymphatic drainage of the lower limbs in patient 1. Primary PLFD was considered for both patients, and a diagnosis of yellow nail syndrome was made in patient 1. Both patients received lymphatic interventional treatment, but all experienced recurrence following the procedure.