Dear Rabbi, My nephew had to have an operation and I made a neder that if the operation will be sucsessful I shall eat only kosher meals. Thank G-d the operation was sucsessful and my nephew is well and healthy. This was six years ago and I would like you please to tell me how I can give up this neder?

You are obligated by the Torah to limit yourself to only kosher food regardless of the neder. If the neder continues to motivate you to keep kosher, it is serving a useful purpose (if it is no longer necessary because you would keep kosher even without it and you are concerned that perhaps unintentionally you might eat something not kosher- you must speak to a local rabbinical authority). May you, your nephew and your entire family be blessed with good health and may you have the merit of many mitzvot- including kashrut- to sustain you!