The Center for Science in the Public Interest accuses the food chain of using the toys to lure children into a pattern of unhealthy eating.
Maritza Gaston's daughters are active and healthy. She says they eat fast food occasionally but when they go to McDonald's the food is not the draw.
"When we end up going there the girls pretty much end up, the toy, the toy, it's all about the toy and they don't eat the food so much," said Gaston.
That's the chief complaint for the CSPI which says the toys draw kids to McDonald's to eat what they say are unhealthy foods. The group is threatening a lawsuit.
"It's not just the meal. It's the technique you are using to get kids to buy a meal," said Michael Jacobson, Center For Science In The Public Interest.
McDonald's agreed years ago to advertise only two selections which offer relatively balanced nutrition. But the center says kids often order less healthy meals when they get there.
A representative from McDonald's said, "we offer a responsible approach to our menu and Happy Meal offerings. We couldn't disagree more with the misrepresentation of our food and marketing practices made by the center. Happy Meals are right sized for kids, a concept which has not changed since the introduction in 1979."
"One particular food in one particular meal doesn't make a healthy or unhealthy diet. It's really the pattern of a diet over time," said nutritionist Cathy Leman. Leman says moderation is the key.
Mike Hessling and his wife Valerie take their kids to McDonald's occasionally as a treat.
"It's the parents' responsibility at some point to have to say no to their kids and to have to teach their kids to make the right decisions," said Mike Hessling.
"They want everything that's bad for them. So do we. We have to tell ourselves no a lot of times, too," said Valerie Hessling.
The spokesperson for the center says they could file a lawsuit within 30 days but first they wanted to give McDonald's a chance to respond.