Survival and mortality of extensive hill ewes are important commercial factors and valuable indicators of welfare, but difficult to study. Body condition scoring is a tried-and-tested management and monitoring tool which has been defined as a good predictor of fitness in ewes and is easily measured under hill farm conditions. This paper presents the results of a study on ewe survival rates in hill conditions in Scotland. Ewe performance and survival rates were measured in two contrasting hill flocks over a five-year period. Statistical analysis showed that mid-pregnancy body condition score was the most reliable indicator of subsequent ewe survival, followed closely by age of the ewe and environmental and management conditions. This study confirms that there are considerable welfare issues related to hill flocks and that improved winter nutritional management is a key component to good welfare and productivity. It also reinforces the view that body condition score is a good quantitative predictor of animal welfare and that poor mid-winter score indicates high risk of mortality, both at the flock and individual ewe level.