A pomegranate contain roughly about 600 seeds. According to some ancient texts there is supposed to be exactly 613 seeds. Interestingly an experiment was conducted at Columbia university and seeds were counted from more than 200 pomegranates. The average was found to be exactly 613! you can find the experiment documented here: http://www.aquaphoenix.com/misc/pomegranate/
The number of seeds in a pomegranate depends on the size of the pomegranate and the size of the seeds within it. On average, there are 600 seeds in a pomegranate. Some, that have large seeds, may only have 200 seeds. There have been some that have contained 1,300 seeds.