I am preparing to give my Daughter and her Fiance a Check of $40,000.00 For a Wedding Gift. Is that a legal non taxable Gift. TY

A gift is never taxable income to the recipient (donee). Nor is the amount of the gift a deduction for the giver (donor).
To the extent the amount given to any donee in a year exceeds 13,000$. That excess is a taxable gift. More on this in a minute.
You can give each of them 13,000$ now and another 7,000$$ on or after January 1. 2013 and all gifts will be excludable gifts. This means you do not meet to file anything with IRS regarding the gifts. If you are married, you and your spouse can give each of them 10,000$ and you will not have to. Make any report to IRS about the gifts.
A taxable gift requires the filing if a Form 709 or 709-A. However, there will not be a gift tax due unless the total of your taxable gifts given in your lifetime exceed the federal estate/gift exemption amount (currently 5 million dollars). The filing of the 709 notifies IRS that you are using up a part of that exemption.

There are two considerations: (1) The tax issue can be easily sorted out by using either your annual exclusion (currently $13,000 per year) or your Lifetime Exclusion (which becomes $1,000,000 on January 1st); (2) If you are later on Medicaid, there is a 5-year 'Look Back' rule that may apply. I'd consult an Ohio Elder Law attorney to sort out your options. Good Luck!

Justin Watling provides an excellent summary of the federal tax impact. Just be aware that some states have gift taxes that differ from the federal. I assume OH doesn't have a gift tax because Mr. Watling didn't reference a state gift tax.
Gifts made within 60 months of applying for Medicaid usually jeopardize Medicaid eligibility so it can be advantageous to make gifts sooner than later. You can give the full $40,000 immediately with no federal gift tax return required if you and your wife split the gifts and the donees are your daughter and her fiance. BUT beware, if the marriage goes South, the fiance would have a claim for gifts to the fiance or your daughter and finance jointly in a divorce whereas if you only gift to your daughter and she keeps the gifts separately, he typically couldn't claim against them in divorce.
Lawrence Friedman, Bridgewater, NJ. Certified as an Elder Law Attorney by the ABA approved National Elder Law Foundation, former Chair NJ State Bar Association Elder and Disabilities Law Section, Member Board of Consultors of NJSBA Real Property, Trusts & Estates Law Section, Vice Chair Special Needs Law Section of National Academy of Elder Law Attorneys, and Master of Laws (L.L.M.) in Taxation from N.Y.U. School of Law. Visit SpecialNeedsNJ.com for articles and Q&A on elder law, special needs, wills, trusts, estates, and tax and SpecialNeedsNJ.com/blog for timely updates. Information on both Avvo and SpecialNeedsNJ.com does not constitute legal advice, as it is general in nature and may not apply to your situation or be subject to important changes. No attorney client relationship exists unless set forth in written engagement terms.

All my colleagues offer good counsel, although I would assume if you can afford to make a cash gift of $40,000 you are not thinking that you will ever need to qualify for Medicaid.
A second consideration is whether or not you are married. If you are married, you and your wife can give up to $46,000 to your daughter and her fiance without being required to file a gift tax return ($13,000 from you to each of them, $13,000 from your wife to each of them).
If you are not married and you want to give them the $40,000, go ahead and do so. You are not required to report the first $26,000. Your accountant can prepare a Form 709 gift tax return for you (filed along with your income taxes by April 15 next year). The fee will probably be $100 to $200 for the filing, but no tax is due. It just comes off your $5 million lifetime gift tax exclusion, leaving you with a gift tax exemption of only $4,974,000! Even if the lifetime exclusion reverts to $1,000,000 in 2013, you will still have $974,000 of exemption remaining. Unless you do, in fact, have a Medicaid planning concern, don't let an arcane federal tax rule stop you from making a gift you wish to make and your daughter would deeply appreciate. Life is too short.

1) There is no Ohio gift tax. 2) I agree with the others. There are a variety of ways to do it. If you are married than you and your husband could give each of them $26,000 ($13,000 x 2) without filing a gift tax return. You can also spread it over time. Remember, the gift will not be subject to income tax, but would be subject to federal gift tax.