It depends on how much randomness you really need. If you needed REALLY random numbers, I suppose you could use Math::TrulyRandom but that's probably overkill for anything short of cryptography. What do you want to do with the random number exactly? You may be better off (in the case of session IDs for example) using a formula like (time) + (a few pseudo-random bytes) or using the Time::HiRes module rather than a random number in order to guarantee uniqueness. Using the time as part of the ID helps narrow the window of opportunity for a duplicate number to occur.