Why weren't federal income taxes taken out of my 2nd job's checks?

If under a certain dollar amount is earned they do not have to take out taxes. My oldest son's on college campus job does not take out taxes, unless he makes over $300 in a pay period. So last year he only had like $37 total taken out. It is supposed to work to his advantage to actually have more to live on, but makes for a sad refund. You should be ok though, having had such a good amount withheld from your primary job.