From the Hellmann's website FAQ page (www.hellmanns.com) on 6/4/2009:
Question: Are Hellmann’s mayonnaise products gluten free?
Answer: At this time, All Hellmann's mayonnaise products are gluten-free (Real, Canola, Light and Reduced Fat). Since product formulations change from time to time, the best advice we can give you is to check the ingredient list on the label. Ingredients that may contain any of the top eight allergens as defined by the FDA, peanuts, tree nuts, soy, fish, seafood, wheat, eggs, and milk or dairy, as well as any ingredient that may contain gluten, are always listed on the label.
Gluten-free information on 2/24/2010 from Best Foods web site (www.bestfoods.com):
At this time, all Hellmann’s® and Best Foods® mayonnaise products are gluten-free.
Gluten and Allergen information