According to Official Guinness Records,
The most wine glasses held in one hand was 39 by Reymond Adina (Philippines) at the Quatre-Gats restaurant in Barcelona, Spain on 24 October 2007.
The number of glasses held in the hand is a matter of pride for Barcelona waiters, and many are adept at carrying dozens of glasses without breaking them.
For a complete list of 2007 records, please visit 2007 Guinness Records in Spain.