You have several options for taking your 401(k) with you, but be aware of the tax consequences. Time your departure to your advantage, if you can.

When you leave your company, you’ll need to do some paperwork – and that includes making a decision about what to do with your 401(k) account. Here are your options:
Rollover your 401(k) into an IRA.
If you leave a job, you have the right to move the money from your 401k account to an IRA without paying any income taxes on it. This is called a “rollover IRA.”
If you decide to roll over your money to an IRA, you can use any financial institution you choose; you are not required to keep the money with the company that was holding your 401(k).
Ask the mutual fund company, bank or brokerage that will manage your IRA for an IRA application. Make sure your former employer does a “direct rollover,” meaning that they write a check directly to the company handling your IRA. If they write the check to you, they will have to withhold 20% in taxes.
Transfer your 401(k) to your new company’s plan.
When you find a new job, you can move the money from your previous employers plan to your new employer’s retirement savings plan (if they offer one) without paying any taxes or penalties. Not all plans will accept rollovers; check with your new employer.
Leave your money in the former employer’s plan.
You won’t be able to make contributions anymore, but this is an option. This is acceptable as a temporary solution while you look for a new job or research where to open your rollover IRA. But it’s not recommended for the long term, because the company may change their investment options over time, and it won’t be easy to ask questions or make changes if you’re no longer working there. If your account balance is less than $5,000, the company may not allow you to leave your money in their plan at all.
Cash out. WARNING! If you take a “lump-sum distribution” instead of rolling your retirement savings account over to an IRA or a new employer’s plan, you will have to pay income taxes on the money. You will also pay a 10% early withdrawal penalty if you’re under age 59 ½. Not only do you lose money, but you lose valuable time in building savings, and may never catch up.

If you’re thinking of quitting your job
Timing is important here. If your company offers matching contributions, don’t walk away and leave that money on the table. Check your plan’s vesting schedule to see whether working longer will let you vest more in your employer contributions. Also, find out when matching contributions are deposited into your account. Some companies make the deposit every pay period; some only once a year. If you leave before that year’s contribution is made, you’ll lose it. *