Half life and survival time of camel red blood cells were determined by labeling with chromium 51. The determinations were made on 3 separate occasions: first, in the summer and then in the winter with water ad libitum followed by a summer of 'chronic dehydration.' The shortest red blood cell survival time was recorded in the winter, and the longest survival and half times were recorded under chronic dehydration in the summer. Normal summer determinations with water ad libitum were similar to those found in other ruminants. The lengthening of the red blood cell life span during dehydration may contribute to the ability of the camel to preserve water.