Between 1966 and 1974, 1260 lidtumours were sent to the histological laboratory of the University Eye Hospital Hamburg. The clinical diagnosis "chalazion" in 138 cases could not be verified histologically in 33 cases. Other benign lesions were diagnosed 23 times and malignant lesions in 10 cases (4 times a Meibom's sebaceous cell carcinoma). The symptoms of all 7 Meibom's sebaceous cell carcinomatas diagnosed histologically during this time (the most common metastasizing lid-tumor in this series) were also analysed as they present the gravest diagnostic error for chalazia. Histologic examination of excised "chalazion"-material must be considered mandatory in all patients with a typical symptomatology, recurrence at the same site, high age, unilateral therapy-resistant keratoconjunctivities and involved regional lymphnodes.