Summary1. The method of counting the large mammals in Lake Manyara National Park is described.2. The results of the count are listed, and the biomass estimated.3. It is suggested that the present population exceeds the carryingcapacity because elephant and buffalo are being made to enter and stay in the Park by increasing cultivation round the boundaries.4. The rise in lake level has aggravated the position by cutting off another route of entry an d exit.5. The extinction of the plains game population is likewise attributed to the new lake level and increased cultivation.