‘Bryn_OED’ provided verifiable evidence from 1953.
DIY is of course an abbreviation of do it yourself, and both terms refer to the carrying out of a task by oneself, especially around the home. The entries for these terms are currently being revised by OED editors. The earliest use of do it yourself as a phrase found so far dates from the nineteenth century (without the later associations with home improvement):
1845 Richard H. Barham Ingoldsby Legends (1905) 288 If it’s business of consequence, Do it yourself!
By 1910, the phrase being used as an adjective:
1910 Popular Science Monthly May 493 At the Boston Tech a method has been in vogue for long that is there deemed highly satisfactory—it is known as the ‘do-it-yourself method’.
But our evidence for the initialism DIY currently goes back only as far as 1955:
1955 Titusville (Pa.) Herald 22 July 8/4 (advt.) DIY means ‘Do It Yourself’ and you can.
1955 Practical Householder Dec. 203/1 A central pool such as a ‘D.I.Y. Club’ from which..tools can be hired is the obvious advantage.
We suspect that earlier evidence for DIY may exist. Can you beat our DIY efforts?
Posted by OED_Editor on 7 November 2012 14.46