Jumbo loans are loans above the Fannie Mae/Freddie Mac conforming loan limit. For most of the country these are loans above $424,100. Jumbo loans generally look and act just like conventional, conforming loans, but since they are held on bank portfolios rather than by Fannie Mae/Freddie Mac there are often a few differences.
Jumbo loans typically require a larger down payment than conventional, conforming loans. A minimum of a 10% down payment is often required with some programs requiring a 20% down payment or more. Jumbo loans also commonly require slightly higher credit scores than conventional, conforming loans.
In most cases, a well-qualified conventional, conforming borrower would have no trouble qualifying for a jumbo loans as long as they are able to afford the higher payment associated with a bigger loan amount.