According to Official Guinness Records,
John 'Lucky' Meisenheimer (USA) has a collection of 4,586 different yo-yo's, as of 22 February 2010, that he has amassed since 1971. Lucky first became fascinated by yo-yo's at junior high school during the 1971 craze. Later, when he went to medical school, he began playing with yo-yo's as a means of relaxation between classes. From that point, Lucky became so dedicated to the art of yo-yo collecting that he self-published a book called Lucky's Collectors Guide to 20th Century Yo-Yo's.
For a complete list of 2010 records, please visit 2010 Guinness Records in United States.