Annulment is a legal process that nullifies a valid marriage. The difference from divorce is that annulment is retroactive. Annulment is also different from legal separation, such that in legal separation, the couple is still considered to be married to each other, and thus, they cannot marry someone else.

What are the grounds for annulment? The law on annulment generally differs from country to country. You can visit http://en.wikipedia.org/wiki/Annulment#Grounds_for_annulment where the various grounds for declaring a marriage annulled are listed and enumerated comprehensively. However, also note that there are several other grounds for marriage annulment depending on which country has the marriage occurred.

In most countries, divorce is more common than annulment, considering that divorce grants more freedom between the spouses. However, annulment is more preferred in conservative countries, the Philippines for example, and in the Roman Catholic Church.

Children born of annulled parents need not worry because they are still considered by law to be legitimate.