What supporting documentation for gambling losses is acceptable from a cash basis taxpayer going into a IRS audit. Taxpayer deducted up to the amount claimed as misc. income. Taxpayer has no banking activity to support cash withdraws etc. Any and all advice truly appreciated.

A daily diary of your wagering activity would be just what you need.

Also, if you gambled in a casino and used their player's card, they can provide you with a printout that will at least partially show your gambling losses and winnings.

This document has been accepted at face value by the IRS as proof of gambling losses.

A phone call to the toll-free number on the back of the player's card will get you the printout in about ten business days.