Generally if you're making a lateral or upward movement in the same field you are going to be OK. Lenders may require you to begin the new job and start recieving paychecks so that they may document your income. It helps if the new job is a salaried position as well. Even hourly full-time is not too tough to document.
If a large amount of your income is commission, bonus, or overtime based then that really muddies the water and you are probably SOL.
The only way to find out is to speak to a local, reputable lending professional
Best of luck
Great question!!! the simple answer is yes and no.
If your work history is consistent and have your tax returns to bolster your work history it should not be a significant problem. If there is a noticeable gap in your work history I recommend drafting a letter that explains the time off from work.
When you go in to speak to a lender (be it a bank or mortgage broker) it is best to come prepared. I encourage my buyers to have a package of information put together first. Items that should be included in the package most times include; 2 years tax returns, several months of pay stubs as well as bank statements. Each lender will have their own list of requirements.
It is also good to shop around for a lender that will give you the best deal for your financial situation. the best credit rate you qualify for, cost of buying down points, etc...
I hope this helps. If you have additional questions feel free to contact me directly.