The study concerning internal and external parasites in deer was conducted in selected Lower Silesia forest inspections from May 1988 till June 1992. Coproscopic method and section were applied. Only in roe-deer the highly extensive invasion of gastrointestinal nematodes was observed (from 50% to 81%, depending on inspections). Most frequent were the Ostertagia (60%) and Nematodirus (30%) types. Another problem, mainly in mouflons, were lung nematodes of Protostrongylidae family, of which the Muellerius capillaris was dominating. Of the external parasites, an infection of Lipoptena cervi was discovered in roe-deer and stag, and Ixodes ricinus appeared most frequently; in Lower Silesia appeared the lung nematodes which could be the reason for disease, particularly in mouflon. Source of the infection were probably sheep brought to that region from Podhale for pasturage.