During the period from April 1991 to July 1992 clinical, hematological, and pathohistological findings of Holstein-friesian calves 47 with bovine leukocyte adhesion deficiency(BLAD, immunologically ascertained), which were referzed to the clinic for diseases of cattle, veterinary school, Hannover, were described. Most cases show poor body condition, rough and dry in haircoat, salivation, gingivitis, reduction of gingiva and alveolar bone, exposing the incisors' necks, loss of teeth, phlegmonous subcutaneous swellings, ulcerated tongue, recurang fever, coughing, dyspnea, pharyngeal and laryngeal stertor, periodical diarrhea, impaired swallowing, placid and less painsensitive. Relevant laboratory findings are persistent leucocytosis(with more than 30,000 up to 150,000 cells per $mm^3$ of blood), marked neutrophilia(without "shift to the left"), hyperproteinemia, and hypergammaglobulinemia. At post-mortem the carcass of BLAD-affected calves is usually emaciated. All lymphnodes of the respiratory and gastrointestinal tract appear markedly activated(swollen). Lesions in the mouth(gingivitis, defective dentition, pulpitis/alveolar paraodontitis, ulcerated tongue), throat and larynx(inflammation/ulceration), and lungs(pneumonic foci) correspond to the clinical symptoms seen on the living animal. There may be ulcers on the prestomachal mucosa, hyperemia of the intestinal mucosa with hyperplasia of Peyer's patches, ulceration and/or intramural abscesses. The spleen shows follicular hyperplasia. Microscopically, both myeloand erythropoesis are markedly activated in the bone marrow ; capillaries in many organs show leucocytostasis.