Background: 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. 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. Results: 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. Bronchoscopy showed massive milky-white casts blocking the airway in patient 2; no casts were observed in patient 1. 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. Conclusions: Primary PLFD is a rare but significant cause of PB in children. Chest CT findings have highly suggestive significance for the diagnosis. The lymphatic interventional procedure may be effective for short-term resolution of symptoms, but prone to recurrence.