Every new mammal or bird in the Amsterdam zoo, without exception, is kept in quarantaine for some weeks and until necessary standard checks are done. The number of mammals in the collection during the period 1967-1973 varied between 729 and 858 belonging to 172 to 208 species. In birds these figures were 1571 and 1803 specimens of 391 to 520 species (table I). The average percentage of deaths in mammals was 12.4% (table II) and in birds 13% (table III). The causes of death (tables IV and V) are arranged under 15 headings for mammals and under 18 for birds; both numbers and percentages are given. During 1967, 1968, and 1969 there were many cases of Yersinia pseudotuberculosis in the nocturnal house. The troubles only stopped after vaccination of all animals already present in the house and of the new ones before housing them. Cases of non-identified infections in psittacine birds (53 victims) and penguins (19 victims) are provided. The same holds true for a skin disease in apes and diabetes in ruminants. A rather detailed report is given on cowpox in indian elephants in 1973. The three females of different age were affected; the male stayed free. All animals recovered after periods ranging from 17 to 57 days. One elephant had serious foot troubles in the same period, the most serious at the left forefoot. It took about 6 weeks before all animals recovered completely. The survival rate of newborn mammals fluctuated between 59% and 66%, at a number of births fluctuating from 164 to 249 a year (table VI). The low rate of 56% for wild ruminants could be raised to 67% by feeding extra minerals to pregnant and nursing females. In birds hatched (table VII) the survival rates varied between 49% and 75%. The low figure is caused by the very bad results with ducks (in 1969 only 25% survival). By changing the accomodation we brought the figure for ducks up to 83% at the end of the period reported upon.